NERC Sea Mammal Research Unit (SMRU) Researchhttp://hdl.handle.net/10023/182
Thu, 24 May 2018 08:58:14 GMT2018-05-24T08:58:14ZNERC Sea Mammal Research Unit (SMRU) Researchhttp://research-repository.st-andrews.ac.uk:80/bitstream/id/3092/smru-wee.gifhttp://hdl.handle.net/10023/182
Local weather and body condition influence habitat use and movements on land of molting female southern elephant seals (Mirounga leonina)http://hdl.handle.net/10023/13416
Southern elephant seals (Mirounga leonina) are known to move and aggregate while molting, but little is known about their behavior on land during this time. In this study, 60 adult females were monitored (23 with GPS tags) during four molting seasons, between 2012 and 2016 at Kerguelen Archipelago, Indian Ocean. Population surveys were recorded each year (N = 230 daily counts), and habitat use was analyzed in relation to the stage of the molt and local weather. Based on stage of molt, habitat use, and movements on land, we classified the molt of elephant seals into three phases: (1) a “search phase” at the initial stage of molt when grass and wallow habitats were used and characterized by greater mean distances travelled on land per day compared with the two other phases; (2) a “resident phase”: during initial and mid‐stage of molt when animals were found in grass and wallow habitats but with less distance moved on land; and (3) a “termination phase” at the final stage of molt where grass and beach habitats were occupied with no change in distances. Windchill and solar radiation influenced individual distances moved per day (mean 590 ± 237.0 m) at the mid‐ and final stage of molt such that animals travelled greater distances on days of low windchill or high solar radiation. Individual variation in distance moved and relative habitat use were also linked to body mass index (BMI) at arrival on the colony, as females with higher BMI moved less and preferred beach habitat. Moreover, the individual rate of molt increased with the use of wallows. Aggregation rate tended to be negatively correlated with distances moved. We therefore suggest that individuals face an energetic trade‐off while molting, balancing energy expenditure between movement and thermoregulation.
The overall study was funded by the Institut Polaire Français Paul-Emile Victor (IPEV program 1037 HEnergES), doctoral fellowships of French Ministry of Higher Education and Research, the University of St Andrews, the Marine Alliance for Science and Technology for Scotland (MASTS), and the Carnegie Trust for the Universities of Scotland.
Sun, 20 May 2018 00:00:00 GMThttp://hdl.handle.net/10023/134162018-05-20T00:00:00ZChaise, Laureline L.Prinet, IrisToscani, CamilleGallon, Susan L.Paterson, WilliamMcCafferty, Dominic J.Théry, MarcAncel, AndréGilbert, CarolineSouthern elephant seals (Mirounga leonina) are known to move and aggregate while molting, but little is known about their behavior on land during this time. In this study, 60 adult females were monitored (23 with GPS tags) during four molting seasons, between 2012 and 2016 at Kerguelen Archipelago, Indian Ocean. Population surveys were recorded each year (N = 230 daily counts), and habitat use was analyzed in relation to the stage of the molt and local weather. Based on stage of molt, habitat use, and movements on land, we classified the molt of elephant seals into three phases: (1) a “search phase” at the initial stage of molt when grass and wallow habitats were used and characterized by greater mean distances travelled on land per day compared with the two other phases; (2) a “resident phase”: during initial and mid‐stage of molt when animals were found in grass and wallow habitats but with less distance moved on land; and (3) a “termination phase” at the final stage of molt where grass and beach habitats were occupied with no change in distances. Windchill and solar radiation influenced individual distances moved per day (mean 590 ± 237.0 m) at the mid‐ and final stage of molt such that animals travelled greater distances on days of low windchill or high solar radiation. Individual variation in distance moved and relative habitat use were also linked to body mass index (BMI) at arrival on the colony, as females with higher BMI moved less and preferred beach habitat. Moreover, the individual rate of molt increased with the use of wallows. Aggregation rate tended to be negatively correlated with distances moved. We therefore suggest that individuals face an energetic trade‐off while molting, balancing energy expenditure between movement and thermoregulation.Mitigation of harm during a novel behavioural response study involving active sonar and wild cetaceanshttp://hdl.handle.net/10023/13322
Some studies of how human activities can affect wild free-ranging animals may be considered to have potential negative outcomes too severe to beethically studied. This creates a societal dilemma involving choices between continuing risky activities with high uncertainty about their potentialeffects on wildlife, often with considerable associated precaution or undertaking focused research to reduce uncertainty, but with some risk of harmfrom either strong response leading to potential stranding or direct physical injury from sound exposure. Recent and ongoing field experimentshave measured the conditions in which wild cetaceans respond to military sonar, and provided insight into the nature of responses. Here mitigationmeasures are reported for one of the first such experiments designed to measure fine-scale behavioural responses to controlled exposures of midfrequency(3–4 kHz) active sonar. The objective was to do so without causing the kinds of physical harm that have been previously observed (e.g.stranding events) and that motivated the study. A critical goal of this experimental study was to identify a response that was safe but that could beused as an indicator of the probability of risk from more extreme or sustained exposure from real military operations. A monitoring and mitigationprotocol was developed using a feedback control procedure for real-time mitigation of potential harm. Experimental protocols were modulatedrelative to indicators of potential risk with the explicit objective of detecting potentially harmful consequences of sound exposure and takingappropriate corrective action. Three categories of mitigation methods were developed and integrated within the experimental protocol incorporatingdesigned, engineered, and operational mitigation measures. Controlled exposure experiments involving free-ranging animals were conducted withoutany evident harm to the experimental subjects, while successfully eliciting behavioural responses that provided meaningful results to informmanagement decisions. This approach demonstrates the importance of careful design of protocols in exposure-response experiments, particularlyin pioneering studies assessing response where both the potential for harm and level of uncertainty may be high.
Fri, 27 Oct 2017 00:00:00 GMThttp://hdl.handle.net/10023/133222017-10-27T00:00:00ZSouthall, BrandonQuick, Nicola JaneHastie, Gordon DrummondTyack, Peter LloydBoyd, Ian LamontSome studies of how human activities can affect wild free-ranging animals may be considered to have potential negative outcomes too severe to beethically studied. This creates a societal dilemma involving choices between continuing risky activities with high uncertainty about their potentialeffects on wildlife, often with considerable associated precaution or undertaking focused research to reduce uncertainty, but with some risk of harmfrom either strong response leading to potential stranding or direct physical injury from sound exposure. Recent and ongoing field experimentshave measured the conditions in which wild cetaceans respond to military sonar, and provided insight into the nature of responses. Here mitigationmeasures are reported for one of the first such experiments designed to measure fine-scale behavioural responses to controlled exposures of midfrequency(3–4 kHz) active sonar. The objective was to do so without causing the kinds of physical harm that have been previously observed (e.g.stranding events) and that motivated the study. A critical goal of this experimental study was to identify a response that was safe but that could beused as an indicator of the probability of risk from more extreme or sustained exposure from real military operations. A monitoring and mitigationprotocol was developed using a feedback control procedure for real-time mitigation of potential harm. Experimental protocols were modulatedrelative to indicators of potential risk with the explicit objective of detecting potentially harmful consequences of sound exposure and takingappropriate corrective action. Three categories of mitigation methods were developed and integrated within the experimental protocol incorporatingdesigned, engineered, and operational mitigation measures. Controlled exposure experiments involving free-ranging animals were conducted withoutany evident harm to the experimental subjects, while successfully eliciting behavioural responses that provided meaningful results to informmanagement decisions. This approach demonstrates the importance of careful design of protocols in exposure-response experiments, particularlyin pioneering studies assessing response where both the potential for harm and level of uncertainty may be high.Clawed forelimbs allow northern seals to eat like their ancient ancestorshttp://hdl.handle.net/10023/13293
Streamlined flippers are often considered the defining feature of seals and sea lions, whose very name ‘pinniped’ comes from the Latin pinna and pedis, meaning ‘fin-footed’. Yet not all pinniped limbs are alike. Whereas otariids (fur seals and sea lions) possess stiff streamlined forelimb flippers, phocine seals (northern true seals) have retained a webbed yet mobile paw bearing sharp claws. Here, we show that captive and wild phocines routinely use these claws to secure prey during processing, enabling seals to tear large fish by stretching them between their teeth and forelimbs. ‘Hold and tear’ processing relies on the primitive forelimb anatomy displayed by phocines, which is also found in the early fossil pinniped Enaliarctos. Phocine forelimb anatomy and behaviour therefore provide a glimpse into how the earliest seals likely fed, and indicate what behaviours may have assisted pinnipeds along their journey from terrestrial to aquatic feeding.
Funding for this project was provided by a Marie Skłodowska-Curie Global Postdoctoral Fellowship (656010/MYSTICETI) to F.G.M, by Marine Scotland to support the wild observations recorded by R.N.H., by an Australian Research Council Future Fellowship FT130100968 to A.R.E., and by an Australian Research Council Linkage Project LP150100403 to A.R.E. and E.M.G.F.
Wed, 18 Apr 2018 00:00:00 GMThttp://hdl.handle.net/10023/132932018-04-18T00:00:00ZHocking, David P.Marx, Felix G.Sattler, RenaeHarris, Robert N.Pollock, Tahlia I.Sorrell, Karina J.Fitzgerald, Erich M.G.McCurry, Matthew R.Evans, Alistair R.Streamlined flippers are often considered the defining feature of seals and sea lions, whose very name ‘pinniped’ comes from the Latin pinna and pedis, meaning ‘fin-footed’. Yet not all pinniped limbs are alike. Whereas otariids (fur seals and sea lions) possess stiff streamlined forelimb flippers, phocine seals (northern true seals) have retained a webbed yet mobile paw bearing sharp claws. Here, we show that captive and wild phocines routinely use these claws to secure prey during processing, enabling seals to tear large fish by stretching them between their teeth and forelimbs. ‘Hold and tear’ processing relies on the primitive forelimb anatomy displayed by phocines, which is also found in the early fossil pinniped Enaliarctos. Phocine forelimb anatomy and behaviour therefore provide a glimpse into how the earliest seals likely fed, and indicate what behaviours may have assisted pinnipeds along their journey from terrestrial to aquatic feeding.Disentangling the causes of protected-species bycatch in gillnet fisherieshttp://hdl.handle.net/10023/13255
Gillnet fisheries are widely thought to pose a conservation threat to many populations of marine mammals, seabirds and turtles. Gillnet fisheries also support a significant proportion of small-scale fishing communities worldwide. Despite a large number of studies on protected species bycatch in recent decades, relatively few have examined the underlying causes of bycatch, and fewer still have looked at the issue from a multi-taxon perspective. We used three bibliographic databases and one search engine to identify studies by year of publication and taxon. The majority of studies on the mechanisms of gillnet bycatch are not accessible through mainstream published literature sources. Many are reported in technical papers, government reports and University theses. We reviewed over 600 published and unpublished studies of bycatch where causal or correlative factors were considered, and identified therein 28 environmental, operational, technical and behavioral factors that might plausibly be associated with higher or lower bycatch rates of the three taxa. Of the factors considered, 11 were found to have been associated with potential bycatch reduction in two out of the three taxa, while three factors (water depth, mesh size and net height) were associated with trends in bycatch rate for all three taxa. These findings provide a basis to guide further experimental work to test hypotheses about which factors most influence bycatch rates, and to explore ways of managing fishing activities and/or improving gear design to minimize the incidental capture of species of conservation concern, whilst ensuring the viability of the fisheries concerned.
We would like to thank the David and Lucile Packard Foundation for funding this work.
Thu, 01 Jun 2017 00:00:00 GMThttp://hdl.handle.net/10023/132552017-06-01T00:00:00ZNorthridge, SimonCoram, Alexander JamesKingston, AlCrawford, RoryGillnet fisheries are widely thought to pose a conservation threat to many populations of marine mammals, seabirds and turtles. Gillnet fisheries also support a significant proportion of small-scale fishing communities worldwide. Despite a large number of studies on protected species bycatch in recent decades, relatively few have examined the underlying causes of bycatch, and fewer still have looked at the issue from a multi-taxon perspective. We used three bibliographic databases and one search engine to identify studies by year of publication and taxon. The majority of studies on the mechanisms of gillnet bycatch are not accessible through mainstream published literature sources. Many are reported in technical papers, government reports and University theses. We reviewed over 600 published and unpublished studies of bycatch where causal or correlative factors were considered, and identified therein 28 environmental, operational, technical and behavioral factors that might plausibly be associated with higher or lower bycatch rates of the three taxa. Of the factors considered, 11 were found to have been associated with potential bycatch reduction in two out of the three taxa, while three factors (water depth, mesh size and net height) were associated with trends in bycatch rate for all three taxa. These findings provide a basis to guide further experimental work to test hypotheses about which factors most influence bycatch rates, and to explore ways of managing fishing activities and/or improving gear design to minimize the incidental capture of species of conservation concern, whilst ensuring the viability of the fisheries concerned.High suckling rates and acoustic crypsis of humpback whale neonates maximise potential for mother–calf energy transferhttp://hdl.handle.net/10023/13227
1. The migration of humpback whales to and from their breeding grounds results in a short, critical time period during which neonatal calves must acquire sufficient energy via suckling from their fasting mothers to survive the long return journey. 2. Understanding neonate suckling behaviour is critical for understanding the energetics and evolution of humpback whale migratory behaviour and for informing conservation efforts, but despite its importance, very little is known about the details, rate and behavioural context of this critical energy transfer. 3. To address this pertinent data gap on calf suckling behaviour, we deployed multi-sensor Dtags on eight humpback whale calves and two mothers allowing us to analyse detailed suckling and acoustic behaviour for a total of 68·8 h. 4. Suckling dives were performed 20·7 ± 7% of the total tagging time with the mothers either resting at the surface or at depth with the calves hanging motionless with roll and pitch angles close to zero. 5. Vocalisations between mother and calf, which included very weak tonal and grunting sounds, were produced more frequently during active dives than suckling dives, suggesting that mechanical stimuli rather than acoustic cues are used to initiate nursing. 6. Use of mechanical cues for initiating suckling and low level vocalisations with an active space of <100 m indicate a strong selection pressure for acoustic crypsis. 7. Such inconspicuous behaviour likely reduces the risk of exposure to eavesdropping predators and male humpback whale escorts that may disrupt the high proportion of time spent nursing and resting, and hence ultimately compromise calf fitness. 8. The small active space of the weak calls between mother and calf is very sensitive to increases in ambient noise from human encroachment thereby increasing the risk of mother–calf separation.
This work was funded by a Sir Walter Murdoch Honorary Professorship along with Carlsberg and FNU funding to P.T.M. L.B. was funded by Murdoch University, and M.J. was funded by the Marine Alliance for Science and Technology, Scotland, and by a Marie Curie Career Integration Grant. Data for this paper are deposited in the Dryad Digital Repository https://doi.org/10.5061/dryad.m8j17 (Videsen et al. 2017).
Tue, 01 Aug 2017 00:00:00 GMThttp://hdl.handle.net/10023/132272017-08-01T00:00:00ZVidesen, Simone K. A.Bejder, LarsJohnson, MarkMadsen, Peter T.1. The migration of humpback whales to and from their breeding grounds results in a short, critical time period during which neonatal calves must acquire sufficient energy via suckling from their fasting mothers to survive the long return journey. 2. Understanding neonate suckling behaviour is critical for understanding the energetics and evolution of humpback whale migratory behaviour and for informing conservation efforts, but despite its importance, very little is known about the details, rate and behavioural context of this critical energy transfer. 3. To address this pertinent data gap on calf suckling behaviour, we deployed multi-sensor Dtags on eight humpback whale calves and two mothers allowing us to analyse detailed suckling and acoustic behaviour for a total of 68·8 h. 4. Suckling dives were performed 20·7 ± 7% of the total tagging time with the mothers either resting at the surface or at depth with the calves hanging motionless with roll and pitch angles close to zero. 5. Vocalisations between mother and calf, which included very weak tonal and grunting sounds, were produced more frequently during active dives than suckling dives, suggesting that mechanical stimuli rather than acoustic cues are used to initiate nursing. 6. Use of mechanical cues for initiating suckling and low level vocalisations with an active space of <100 m indicate a strong selection pressure for acoustic crypsis. 7. Such inconspicuous behaviour likely reduces the risk of exposure to eavesdropping predators and male humpback whale escorts that may disrupt the high proportion of time spent nursing and resting, and hence ultimately compromise calf fitness. 8. The small active space of the weak calls between mother and calf is very sensitive to increases in ambient noise from human encroachment thereby increasing the risk of mother–calf separation.Using self-organizing maps to classify humpback whale song units and quantify their similarityhttp://hdl.handle.net/10023/13109
Classification of vocal signals can be undertaken using a wide variety of qualitative and quantitative techniques. Using east Australian humpback whale song from 2002-2014, a subset of vocal signals were acoustically measured and then classified using a self-organizing map (SOM). The SOM created 1) an acoustic dictionary of units representing the song’s repertoire, and 2) Cartesian distance measurements among all unit types (SOM nodes). Utilizing the SOM dictionary as a guide, additional song recordings from east Australia were rapidly (manually) transcribed. To assess the similarity in song sequences, the Cartesian distance output from the SOM was applied in Levenshtein distance similarity analyses as a weighting factor to better incorporate unit similarity in the calculation (previously a qualitative process). SOMs provide a more robust and repeatable means of categorizing acoustic signals along with a clear quantitative measurement of sound type similarity based on acoustic features. This method can be utilized for a wide variety of acoustic databases especially those containing very large datasets, and be applied across the vocalization research community to help address concerns surrounding inconsistency in manual classification.
E.C.G. was funded by a Royal Society Newton International Fellowship.
Tue, 10 Oct 2017 00:00:00 GMThttp://hdl.handle.net/10023/131092017-10-10T00:00:00ZAllen, Jenny A.Murray, AnitaNoad, Michael J.Dunlop, Rebecca A.Garland, Ellen ClareClassification of vocal signals can be undertaken using a wide variety of qualitative and quantitative techniques. Using east Australian humpback whale song from 2002-2014, a subset of vocal signals were acoustically measured and then classified using a self-organizing map (SOM). The SOM created 1) an acoustic dictionary of units representing the song’s repertoire, and 2) Cartesian distance measurements among all unit types (SOM nodes). Utilizing the SOM dictionary as a guide, additional song recordings from east Australia were rapidly (manually) transcribed. To assess the similarity in song sequences, the Cartesian distance output from the SOM was applied in Levenshtein distance similarity analyses as a weighting factor to better incorporate unit similarity in the calculation (previously a qualitative process). SOMs provide a more robust and repeatable means of categorizing acoustic signals along with a clear quantitative measurement of sound type similarity based on acoustic features. This method can be utilized for a wide variety of acoustic databases especially those containing very large datasets, and be applied across the vocalization research community to help address concerns surrounding inconsistency in manual classification.Species differences in egocentric navigation : the effect of burrowing ecology on a spatial cognitive trait in micehttp://hdl.handle.net/10023/13044
Efficient navigation is a critical component of fitness for most animals. While most species use a combination of allocentric (external) and egocentric (internal) cues to navigate through their environment, subterranean environments present a unique challenge in that visually mediated allocentric cues are unavailable. The relationship between egocentric spatial cognition and species differences in ecology is surprisingly understudied. We used a maze-learning task to test for differences in egocentric navigation between two closely related species of mice, the eastern house mouse, Mus musculus musculus, and the mound-building mouse, Mus spicilegus. The two species are sympatric in Eastern Europe and overlap in summer habitat use but differ dramatically in winter space use: whereas house mice occupy anthropogenic structures, mound-building mice survive the winter underground in intricate burrow systems. Given species differences in burrowing ecology, we predicted that M. spicilegus would learn the maze significantly faster than M. m. musculus when tested in complete darkness, a condition that eliminated allocentric spatial information and served as a proxy for the subterranean environment. We found strong support for this prediction. In contrast, the two species performed equally well when different mice were tested in the same maze with lights on. This context-specific species difference in spatial cognition suggests that enhanced egocentric navigation in M. spicilegus is an adaptation to the burrow systems on which the overwinter survival of young mound-building mice depends. The results of this study highlight the importance of ecological adaptations to the evolution of cognitive traits.
This study was funded by start-up funds from Oklahoma State University to P.C.
Mon, 01 May 2017 00:00:00 GMThttp://hdl.handle.net/10023/130442017-05-01T00:00:00ZBruck, Jason N.Allen, Noah A.Brass, Kelsey E.Horn, Brian A.Campbell, PollyEfficient navigation is a critical component of fitness for most animals. While most species use a combination of allocentric (external) and egocentric (internal) cues to navigate through their environment, subterranean environments present a unique challenge in that visually mediated allocentric cues are unavailable. The relationship between egocentric spatial cognition and species differences in ecology is surprisingly understudied. We used a maze-learning task to test for differences in egocentric navigation between two closely related species of mice, the eastern house mouse, Mus musculus musculus, and the mound-building mouse, Mus spicilegus. The two species are sympatric in Eastern Europe and overlap in summer habitat use but differ dramatically in winter space use: whereas house mice occupy anthropogenic structures, mound-building mice survive the winter underground in intricate burrow systems. Given species differences in burrowing ecology, we predicted that M. spicilegus would learn the maze significantly faster than M. m. musculus when tested in complete darkness, a condition that eliminated allocentric spatial information and served as a proxy for the subterranean environment. We found strong support for this prediction. In contrast, the two species performed equally well when different mice were tested in the same maze with lights on. This context-specific species difference in spatial cognition suggests that enhanced egocentric navigation in M. spicilegus is an adaptation to the burrow systems on which the overwinter survival of young mound-building mice depends. The results of this study highlight the importance of ecological adaptations to the evolution of cognitive traits.Using agent-based models to understand the role of individuals in the song evolution of humpback whales (Megaptera novaeangliae)http://hdl.handle.net/10023/12929
Male humpback whales produce hierarchically structured songs, primarily during the breeding season. These songs gradually change over the course of the breeding season, and are generally population specific. However, instances have been recorded of more rapid song changes where the song of a population can be replaced by the song of an adjacent population. The mechanisms that drive these changes are not currently understood, and difficulties in tracking individual whales over long migratory routes mean field studies to understand these mechanisms are not feasible. In order to help understand the mechanisms that drive these song changes, we present here a spatially explicit agent-based model inspired by methods used in computer music research. We model the migratory patterns of humpback whales, a simple song learning and production method coupled with sound transmission loss, and how often singing occurs during these migratory cycles. This model is then extended to include learning biases that may be responsible for driving changes in the song, such as a bias towards novel song, production errors, and the coupling of novel song bias and production errors. While none of the methods showed population song replacement, our model shows that shared feeding grounds where conspecifics are able to mix provides key opportunities for cultural transmission, and production errors facilitated gradually changing songs. Our results point towards other learning biases being necessary in order for population song replacement to occur.
Mon, 01 Jan 2018 00:00:00 GMThttp://hdl.handle.net/10023/129292018-01-01T00:00:00ZMcloughlin, MichaelLamoni, LucaGarland, Ellen C.Ingram, SimonKirke, AlexisNoad, Michael J.Rendell, LukeMiranda, EduardoMale humpback whales produce hierarchically structured songs, primarily during the breeding season. These songs gradually change over the course of the breeding season, and are generally population specific. However, instances have been recorded of more rapid song changes where the song of a population can be replaced by the song of an adjacent population. The mechanisms that drive these changes are not currently understood, and difficulties in tracking individual whales over long migratory routes mean field studies to understand these mechanisms are not feasible. In order to help understand the mechanisms that drive these song changes, we present here a spatially explicit agent-based model inspired by methods used in computer music research. We model the migratory patterns of humpback whales, a simple song learning and production method coupled with sound transmission loss, and how often singing occurs during these migratory cycles. This model is then extended to include learning biases that may be responsible for driving changes in the song, such as a bias towards novel song, production errors, and the coupling of novel song bias and production errors. While none of the methods showed population song replacement, our model shows that shared feeding grounds where conspecifics are able to mix provides key opportunities for cultural transmission, and production errors facilitated gradually changing songs. Our results point towards other learning biases being necessary in order for population song replacement to occur.Comparing methods suitable for monitoring marine mammals in low visibility conditions during seismic surveyshttp://hdl.handle.net/10023/12898
Loud sound emitted during offshore industrial activities can impact marine mammals. Regulations typically prescribe marine mammal monitoring before and/or during these activities to implement mitigation measures that minimise potential acoustic impacts. Using seismic surveys under low visibility conditions as a case study, we review which monitoring methods are suitable and compare their relative strengths and weaknesses. Passive acoustic monitoring has been implemented as either a complementary or alternative method to visual monitoring in low visibility conditions. Other methods such as RADAR, active sonar and thermal infrared have also been tested, but are rarely recommended by regulatory bodies. The efficiency of the monitoring method(s) will depend on the animal behaviour and environmental conditions, however, using a combination of complementary systems generally improves the overall detection performance. We recommend that the performance of monitoring systems, over a range of conditions, is explored in a modelling framework for a variety of species.
Funding: This work was supported by the Joint Industry Programme on E&P Sound and Marine Life - Phase III. TAM was partially supported by CEAUL (funded by FCT - Fundação para a Ciência e a Tecnologia, Portugal, through the project UID/MAT/00006/2013).
Mon, 01 Jan 2018 00:00:00 GMThttp://hdl.handle.net/10023/128982018-01-01T00:00:00ZVerfuss, Ursula K.Gillespie, DouglasGordon, JonathanMarques, Tiago A.Miller, BriannePlunkett, RachaelTheriault, James A.Tollit, Dominic J.Zitterbart, Daniel P.Hubert, PhilippeThomas, LenLoud sound emitted during offshore industrial activities can impact marine mammals. Regulations typically prescribe marine mammal monitoring before and/or during these activities to implement mitigation measures that minimise potential acoustic impacts. Using seismic surveys under low visibility conditions as a case study, we review which monitoring methods are suitable and compare their relative strengths and weaknesses. Passive acoustic monitoring has been implemented as either a complementary or alternative method to visual monitoring in low visibility conditions. Other methods such as RADAR, active sonar and thermal infrared have also been tested, but are rarely recommended by regulatory bodies. The efficiency of the monitoring method(s) will depend on the animal behaviour and environmental conditions, however, using a combination of complementary systems generally improves the overall detection performance. We recommend that the performance of monitoring systems, over a range of conditions, is explored in a modelling framework for a variety of species.Assessing cetacean surveys throughout the Mediterranean Sea : a gap analysis in environmental spacehttp://hdl.handle.net/10023/12829
Heterogeneous data collection in the marine environment has led to large gaps in our knowledge of marine species distributions. To fill these gaps, models calibrated on existing data may be used to predict species distributions in unsampled areas, given that available data are sufficiently representative. Our objective was to evaluate the feasibility of mapping cetacean densities across the entire Mediterranean Sea using models calibrated on available survey data and various environmental covariates. We aggregated 302,481 km of line transect survey effort conducted in the Mediterranean Sea within the past 20 years by many organisations. Survey coverage was highly heterogeneous geographically and seasonally: large data gaps were present in the eastern and southern Mediterranean and in non-summer months. We mapped the extent of interpolation versus extrapolation and the proportion of data nearby in environmental space when models calibrated on existing survey data were used for prediction across the entire Mediterranean Sea. Using model predictions to map cetacean densities in the eastern and southern Mediterranean, characterised by warmer, less productive waters, and more intense eddy activity, would lead to potentially unreliable extrapolations. We stress the need for systematic surveys of cetaceans in these environmentally unique Mediterranean waters, particularly in non-summer months.
Authors thank United States Fleet Forces Command and Naval Facilities Engineering Command Atlantic for funding and support for the development of this gap analysis.
Thu, 15 Feb 2018 00:00:00 GMThttp://hdl.handle.net/10023/128292018-02-15T00:00:00ZMannocci, LauraRoberts, Jason J.Halpin, Patrick N.Authier, MatthieuBoisseau, OliverBradai, Mohamed NejmeddineCañadas, AnaChicote, CarlaDavid, LéaDi-Méglio, NathalieFortuna, Caterina M.Frantzis, AlexandrosGazo, ManelGenov, TilenHammond, Philip S.Holcer, DraškoKaschner, KristinKerem, DaniLauriano, GiancarloLewis, TimNotarbartolo di Sciara, GiuseppePanigada, SimoneRaga, Juan AntonioScheinin, AviadRidoux, VincentVella, AdrianaVella, JosephHeterogeneous data collection in the marine environment has led to large gaps in our knowledge of marine species distributions. To fill these gaps, models calibrated on existing data may be used to predict species distributions in unsampled areas, given that available data are sufficiently representative. Our objective was to evaluate the feasibility of mapping cetacean densities across the entire Mediterranean Sea using models calibrated on available survey data and various environmental covariates. We aggregated 302,481 km of line transect survey effort conducted in the Mediterranean Sea within the past 20 years by many organisations. Survey coverage was highly heterogeneous geographically and seasonally: large data gaps were present in the eastern and southern Mediterranean and in non-summer months. We mapped the extent of interpolation versus extrapolation and the proportion of data nearby in environmental space when models calibrated on existing survey data were used for prediction across the entire Mediterranean Sea. Using model predictions to map cetacean densities in the eastern and southern Mediterranean, characterised by warmer, less productive waters, and more intense eddy activity, would lead to potentially unreliable extrapolations. We stress the need for systematic surveys of cetaceans in these environmentally unique Mediterranean waters, particularly in non-summer months.Not just fat : investigating the proteome of cetacean blubber tissuehttp://hdl.handle.net/10023/12818
Mammalian adipose tissue is increasingly being recognized as an endocrine organ involved in the regulation of a number of metabolic processes and pathways. It responds to signals from different hormone systems and the central nervous system, and expresses a variety of protein factors with important paracrine and endocrine functions. This study presents a first step towards the systematic analysis of the protein content of cetacean adipose tissue, the blubber, in order to investigate the kinds of proteins present and their relative abundance. Full depth blubber subsamples were collected from dead-stranded harbour porpoises (Phocoena phocoena) (n = 21). Three total protein extraction methods were trialled, and the highest total protein yields with the lowest extraction variability were achieved using a RIPA cell lysis and extraction buffer based protocol. Extracted proteins were separated using 1D Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoresis (SDS-PAGE), and identified using nanoflow Liquid Chromatography Electrospray Ionization in tandem with Mass Spectrometry (nLC-ESI–MS/MS). A range of proteins were identified (n = 295) and classed into eight functional groups, the most abundant of which were involved in cell function and metabolism (45%), immune response and inflammation (15%) and lipid metabolism (11%). These proteins likely originate both from the various cell types within the blubber tissue itself, and from the circulation. They therefore have the potential to capture information on the cellular and physiological stresses experienced by individuals at the time of sampling. The importance of this proteomic approach is two-fold: Firstly, it could help to assign novel functions to marine mammal blubber in keeping with current understanding of the multi-functional role of adipose tissue in other mammals. Secondly, it could lead to the development of a suite of biomarkers to better monitor the physiological state and health of live individuals though remote blubber biopsy sampling.
Mon, 01 Jan 2018 00:00:00 GMThttp://hdl.handle.net/10023/128182018-01-01T00:00:00ZKershaw, Joanna LouiseBotting, Catherine HelenBrownlow, AndrewHall, Ailsa JaneMammalian adipose tissue is increasingly being recognized as an endocrine organ involved in the regulation of a number of metabolic processes and pathways. It responds to signals from different hormone systems and the central nervous system, and expresses a variety of protein factors with important paracrine and endocrine functions. This study presents a first step towards the systematic analysis of the protein content of cetacean adipose tissue, the blubber, in order to investigate the kinds of proteins present and their relative abundance. Full depth blubber subsamples were collected from dead-stranded harbour porpoises (Phocoena phocoena) (n = 21). Three total protein extraction methods were trialled, and the highest total protein yields with the lowest extraction variability were achieved using a RIPA cell lysis and extraction buffer based protocol. Extracted proteins were separated using 1D Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoresis (SDS-PAGE), and identified using nanoflow Liquid Chromatography Electrospray Ionization in tandem with Mass Spectrometry (nLC-ESI–MS/MS). A range of proteins were identified (n = 295) and classed into eight functional groups, the most abundant of which were involved in cell function and metabolism (45%), immune response and inflammation (15%) and lipid metabolism (11%). These proteins likely originate both from the various cell types within the blubber tissue itself, and from the circulation. They therefore have the potential to capture information on the cellular and physiological stresses experienced by individuals at the time of sampling. The importance of this proteomic approach is two-fold: Firstly, it could help to assign novel functions to marine mammal blubber in keeping with current understanding of the multi-functional role of adipose tissue in other mammals. Secondly, it could lead to the development of a suite of biomarkers to better monitor the physiological state and health of live individuals though remote blubber biopsy sampling.Categorizing click trains to increase taxonomic precision in echolocation click loggershttp://hdl.handle.net/10023/12721
Passive acoustic monitoring is an efficient way to study acoustically active animals but species identification remains a major challenge. C-PODs are popular logging devices that automatically detect odontocete echolocation clicks. However, the accompanying analysis software does not distinguish between delphinid species. Click train features logged by C-PODs were compared to frequency spectra from adjacently deployed continuous recorders. A generalized additive model was then used to categorize C-POD click trains into three groups: broadband click trains, produced by bottlenose dolphin (Tursiops truncatus) or common dolphin (Delphinus delphis), frequency-banded click trains, produced by Risso's (Grampus griseus) or white beaked dolphins (Lagenorhynchus albirostris), and unknown click trains. Incorrect categorization rates for broadband and frequency banded clicks were 0.02 (SD 0.01), but only 30% of the click trains met the categorization threshold. To increase the proportion of categorized click trains, model predictions were pooled within acoustic encounters and a likelihood ratio threshold was used to categorize encounters. This increased the proportion of the click trains meeting either the broadband or frequency banded categorization threshold to 98%. Predicted species distribution at the 30 study sites matched well to visual sighting records from the region.
L.R. and K.J.P. were supported by Marine Scotland Science and the Marine Alliance for Science and Technology for Scotland (MASTS) pooling initiative and their support is gratefully acknowledged. MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions.
Tue, 01 Aug 2017 00:00:00 GMThttp://hdl.handle.net/10023/127212017-08-01T00:00:00ZPalmer, K. J.Brookes, KateRendell, LukePassive acoustic monitoring is an efficient way to study acoustically active animals but species identification remains a major challenge. C-PODs are popular logging devices that automatically detect odontocete echolocation clicks. However, the accompanying analysis software does not distinguish between delphinid species. Click train features logged by C-PODs were compared to frequency spectra from adjacently deployed continuous recorders. A generalized additive model was then used to categorize C-POD click trains into three groups: broadband click trains, produced by bottlenose dolphin (Tursiops truncatus) or common dolphin (Delphinus delphis), frequency-banded click trains, produced by Risso's (Grampus griseus) or white beaked dolphins (Lagenorhynchus albirostris), and unknown click trains. Incorrect categorization rates for broadband and frequency banded clicks were 0.02 (SD 0.01), but only 30% of the click trains met the categorization threshold. To increase the proportion of categorized click trains, model predictions were pooled within acoustic encounters and a likelihood ratio threshold was used to categorize encounters. This increased the proportion of the click trains meeting either the broadband or frequency banded categorization threshold to 98%. Predicted species distribution at the 30 study sites matched well to visual sighting records from the region.Can fear conditioning repel California sea lions from fishing activities?http://hdl.handle.net/10023/12649
Marine mammal interactions with fisheries create conflicts that can threaten human safety, economic interests and marine mammal survival. A deterrent that capitalizes on learning mechanisms, like fear conditioning, may enhance success while simultaneously balancing welfare concerns and reduce noise pollution. During fear conditioning, individuals learn the cues that precede the dangerous stimuli, and respond by avoiding the painful situations. We tested the efficacy of fear conditioning using acoustic stimuli for reducing California sea lion Zalophus californianus interactions from two fishing contexts in California, USA; bait barges and recreational fishing vessels. We performed conditioning trials on 24 individual sea lions interacting with bait barges. We tested for acquisition of conditioned fear by pairing a neutral tone with a startle stimulus. Avoidance was strongest in response to the startle stimulus alone, but low when paired with a neutral tone. From actively fishing vessels, we tested for fear conditioning by exposing sea lions to a neutral tone followed by a startle pulse, a startle pulse alone or a no sound control. We conducted playbacks from 146 (including 48 no sound control) stops over two summer fishing seasons (2013, 2014). The startle stimulus decreased surfacing frequency, reduced bait foraging and increased surfacing distance from the vessel while the conditioned stimulus only caused a mild reduction in surfacing frequency with no other behavioral change. Exposing animals to a pair of a conditioned stimulus with a startle pulse did not achieve the intended management outcome. Rather, it generated evidence (in two study contexts) of immediate learning that led to the reduction of the unconditioned response. Taken together, our results suggest that for fear conditioning to be applied as a non-lethal deterrent, careful consideration has to be given to individual behavior, the unconditioned/conditioned responses and the overall management goals.
Z.S. was supported by a NSF predoctoral fellowship and by a grant from the LaKretz Center for California Conservation Science. D.T.B. was supported by the NSF during manuscript preparation.
Sun, 01 Oct 2017 00:00:00 GMThttp://hdl.handle.net/10023/126492017-10-01T00:00:00ZSchakner, Zachary A.Götz, ThomasJanik, Vincent M.Blumstein, Daniel T.Marine mammal interactions with fisheries create conflicts that can threaten human safety, economic interests and marine mammal survival. A deterrent that capitalizes on learning mechanisms, like fear conditioning, may enhance success while simultaneously balancing welfare concerns and reduce noise pollution. During fear conditioning, individuals learn the cues that precede the dangerous stimuli, and respond by avoiding the painful situations. We tested the efficacy of fear conditioning using acoustic stimuli for reducing California sea lion Zalophus californianus interactions from two fishing contexts in California, USA; bait barges and recreational fishing vessels. We performed conditioning trials on 24 individual sea lions interacting with bait barges. We tested for acquisition of conditioned fear by pairing a neutral tone with a startle stimulus. Avoidance was strongest in response to the startle stimulus alone, but low when paired with a neutral tone. From actively fishing vessels, we tested for fear conditioning by exposing sea lions to a neutral tone followed by a startle pulse, a startle pulse alone or a no sound control. We conducted playbacks from 146 (including 48 no sound control) stops over two summer fishing seasons (2013, 2014). The startle stimulus decreased surfacing frequency, reduced bait foraging and increased surfacing distance from the vessel while the conditioned stimulus only caused a mild reduction in surfacing frequency with no other behavioral change. Exposing animals to a pair of a conditioned stimulus with a startle pulse did not achieve the intended management outcome. Rather, it generated evidence (in two study contexts) of immediate learning that led to the reduction of the unconditioned response. Taken together, our results suggest that for fear conditioning to be applied as a non-lethal deterrent, careful consideration has to be given to individual behavior, the unconditioned/conditioned responses and the overall management goals.The devil is in the detail : quantifying vocal variation in a complex, multi-levelled, and rapidly evolving displayhttp://hdl.handle.net/10023/12641
Identifying and quantifying variation in vocalizations is fundamental to advancing our understanding of processes such as speciation, sexual selection, and cultural evolution. The song of the humpback whale (Megaptera novaeangliae) presents an extreme example of complexity and cultural evolution. It is a long, hierarchically structured vocal display that undergoes constant evolutionary change. Obtaining robust metrics to quantify song variation at multiple scales (from a sound through to population variation across the seascape) is a substantial challenge. Here, we present a method to quantify song similarity at multiple levels within the hierarchy. To incorporate the complexity of these multiple levels, the calculation of similarity is weighted by measurements of sound units (lower levels within the display) to bridge the gap in information between upper and lower levels. Results demonstrate that the inclusion of weighting provides a more realistic and robust representation of song similarity at multiple levels within the display. Our method permits robust quantification of cultural patterns and processes that will also contribute to the conservation management of endangered humpback whale populations, and is applicable to any hierarchically structured signal sequence.
E.C.G. was funded by a Royal Society Newton International Fellowship. L.R. was supported by the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland) and their support is gratefully acknowledged. MASTS is funded by the Scottish Funding Council (Grant Reference No. HR09011) and contributing institutions. Some funding and logistical support was provided to M.M.P. by the National Oceanic Society (USA), Dolphin & Whale Watching Expeditions (French Polynesia), Vista Press (USA), and the International Fund for Animal Welfare (via the South Pacific Whale Research Consortium).
Mon, 31 Jul 2017 00:00:00 GMThttp://hdl.handle.net/10023/126412017-07-31T00:00:00ZGarland, Ellen C.Rendell, LukeLilley, Matthew S.Poole, M. MichaelAllen, JennyNoad, Michael J.Identifying and quantifying variation in vocalizations is fundamental to advancing our understanding of processes such as speciation, sexual selection, and cultural evolution. The song of the humpback whale (Megaptera novaeangliae) presents an extreme example of complexity and cultural evolution. It is a long, hierarchically structured vocal display that undergoes constant evolutionary change. Obtaining robust metrics to quantify song variation at multiple scales (from a sound through to population variation across the seascape) is a substantial challenge. Here, we present a method to quantify song similarity at multiple levels within the hierarchy. To incorporate the complexity of these multiple levels, the calculation of similarity is weighted by measurements of sound units (lower levels within the display) to bridge the gap in information between upper and lower levels. Results demonstrate that the inclusion of weighting provides a more realistic and robust representation of song similarity at multiple levels within the display. Our method permits robust quantification of cultural patterns and processes that will also contribute to the conservation management of endangered humpback whale populations, and is applicable to any hierarchically structured signal sequence.Song hybridization events during revolutionary song change provide insights into cultural transmission in humpback whaleshttp://hdl.handle.net/10023/12604
Cultural processes occur in a wide variety of animal taxa, from insects to cetaceans. The songs of humpback whales are one of the most striking examples of the transmission of a cultural trait and social learning in any nonhuman animal. To understand how songs are learned, we investigate rare cases of song hybridization, where parts of an existing song are spliced with a new one, likely before an individual totally adopts the new song. Song unit sequences were extracted from over 9,300 phrases recorded during two song revolutions across the South Pacific Ocean, allowing fine-scale analysis of composition and sequencing. In hybrid songs the current and new songs were spliced together in two specific ways: (i) singers placed a single hybrid phrase, in which content from both songs were combined, between the two song types when transitioning from one to the other, and/or (ii) singers spliced complete themes from the revolutionary song into the current song. Sequence analysis indicated that both processes were governed by structural similarity rules. Hybrid phrases or theme substitutions occurred at points in the songs where both songs contained “similar sounds arranged in a similar pattern.” Songs appear to be learned as segments (themes/phrase types), akin to birdsong and human language acquisition, and these can be combined in predictable ways if the underlying structural pattern is similar. These snapshots of song change provide insights into the mechanisms underlying song learning in humpback whales, and comparative perspectives on the evolution of human language and culture.
E.C.G. and this study were supported by a Newton International Fellowship from the Royal Society of London; L.L. was supported by Leverhulme Trust Research Project Grant RPG-2013-367; L.R. was supported by the Marine Alliance for Science and Technology for Scotland (MASTS) pooling initiative. MASTS is funded by the Scottish Funding Council (Grant HR09011) and contributing institutions. Song recordings in eastern Australia were funded by the Scott Foundation, the US Office of Naval Research, and the Australian Defence Science and Technology Organization. We thank everyone involved with this project. Some funding and logistical support was provided to M.M.P. by the US National Oceanic Society, Dolphin & Whale Watching Expeditions (French Polynesia), Vista Press, and the International Fund for Animal Welfare (via the South Pacific Whale Research Consortium).
Tue, 25 Jul 2017 00:00:00 GMThttp://hdl.handle.net/10023/126042017-07-25T00:00:00ZGarland, Ellen C.Rendell, LukeLamoni, LucaPoole, M. MichaelNoad, Michael J.Cultural processes occur in a wide variety of animal taxa, from insects to cetaceans. The songs of humpback whales are one of the most striking examples of the transmission of a cultural trait and social learning in any nonhuman animal. To understand how songs are learned, we investigate rare cases of song hybridization, where parts of an existing song are spliced with a new one, likely before an individual totally adopts the new song. Song unit sequences were extracted from over 9,300 phrases recorded during two song revolutions across the South Pacific Ocean, allowing fine-scale analysis of composition and sequencing. In hybrid songs the current and new songs were spliced together in two specific ways: (i) singers placed a single hybrid phrase, in which content from both songs were combined, between the two song types when transitioning from one to the other, and/or (ii) singers spliced complete themes from the revolutionary song into the current song. Sequence analysis indicated that both processes were governed by structural similarity rules. Hybrid phrases or theme substitutions occurred at points in the songs where both songs contained “similar sounds arranged in a similar pattern.” Songs appear to be learned as segments (themes/phrase types), akin to birdsong and human language acquisition, and these can be combined in predictable ways if the underlying structural pattern is similar. These snapshots of song change provide insights into the mechanisms underlying song learning in humpback whales, and comparative perspectives on the evolution of human language and culture.Intrinsic and extrinsic factors drive ontogeny of early-life at-sea behaviour in a marine top predatorhttp://hdl.handle.net/10023/12410
Young animals must learn to forage effectively to survive the transition from parental provisioning to independent feeding. Rapid development of successful foraging strategies is particularly important for capital breeders that do not receive parental guidance after weaning. The intrinsic and extrinsic drivers of variation in ontogeny of foraging are poorly understood for many species. Grey seals (Halichoerus grypus) are typical capital breeders; pups are abandoned on the natal site after a brief suckling phase, and must develop foraging skills without external input. We collected location and dive data from recently-weaned grey seal pups from two regions of the United Kingdom (the North Sea and the Celtic and Irish Seas) using animal-borne telemetry devices during their first months of independence at sea. Dive duration, depth, bottom time, and benthic diving increased over the first 40 days. The shape and magnitude of changes differed between regions. Females consistently had longer bottom times, and in the Celtic and Irish Seas they used shallower water than males. Regional sex differences suggest that extrinsic factors, such as water depth, contribute to behavioural sexual segregation. We recommend that conservation strategies consider movements of young naïve animals in addition to those of adults to account for developmental behavioural changes.
Tags, and their deployments, were funded by the Welsh Assembly Government (Welsh colonies; project no. JER3688), Marine Scotland (Stroma and Muckle Green Holm; project no. CR/2009/48), the Natural Environment Research Council (NERC) (Isle of May) and SMRU Instrumentation (Isle of May). MIDC studentship is co-funded by Plymouth University School of Biological & Marine Sciences and NERC. DJFR, CJB & DT are supported by National Capability funding from NERC to SMRU (grant no. SMRU1001).
Tue, 14 Nov 2017 00:00:00 GMThttp://hdl.handle.net/10023/124102017-11-14T00:00:00ZCarter, Matt I. D.Russell, Deborah J. F.Embling, Clare B.Blight, Clint J.Thompson, DavidHosegood, Philip J.Bennett, Kimberley A.Young animals must learn to forage effectively to survive the transition from parental provisioning to independent feeding. Rapid development of successful foraging strategies is particularly important for capital breeders that do not receive parental guidance after weaning. The intrinsic and extrinsic drivers of variation in ontogeny of foraging are poorly understood for many species. Grey seals (Halichoerus grypus) are typical capital breeders; pups are abandoned on the natal site after a brief suckling phase, and must develop foraging skills without external input. We collected location and dive data from recently-weaned grey seal pups from two regions of the United Kingdom (the North Sea and the Celtic and Irish Seas) using animal-borne telemetry devices during their first months of independence at sea. Dive duration, depth, bottom time, and benthic diving increased over the first 40 days. The shape and magnitude of changes differed between regions. Females consistently had longer bottom times, and in the Celtic and Irish Seas they used shallower water than males. Regional sex differences suggest that extrinsic factors, such as water depth, contribute to behavioural sexual segregation. We recommend that conservation strategies consider movements of young naïve animals in addition to those of adults to account for developmental behavioural changes.Individual, ecological, and anthropogenic inﬂuences on activity budgets of long-ﬁnned pilot whaleshttp://hdl.handle.net/10023/12408
Time allocation to different activities and habitats enables individuals to modulate their perceived risks and access to resources, and can reveal important trade-offs between fitness-enhancing activities (e.g., feeding vs. social behavior). Species with long reproductive cycles and high parental investment, such as marine mammals, rely on such behavioral plasticity to cope with rapid environmental change, including anthropogenic stressors. We quantified activity budgets of free-ranging long-finned pilot whales in order to assess individual time trade-offs between foraging and other behaviors in different individual and ecological contexts, and during experimental sound exposures. The experiments included 1-2 and 6-7 kHz naval sonar exposures (a potential anthropogenic stressor), playback of killer whale (a potential predator/competitor) vocalizations, and negative controls. We combined multiple time series data from digital acoustic recording tags (DTAG) as well as group-level social behavior data from visual observations of tagged whales at the surface. The data were classified into near-surface behaviors and dive types (using a hidden Markov model for dive transitions) and aggregated into time budgets. On average, individuals (N=19) spent most of their time (69%) resting and transiting near surface, 21% in shallow dives (depth <40m), and only 10% of their time in deep foraging dives, of which 65% reached a depth 10m from the sea bottom. Individuals in the largest of three body size classes or accompanied by calves tended to spend more time foraging than others. Simultaneous tagging of pairs of individuals showed that up to 50% of the activity budget was synchronized between conspecifics with decreased synchrony during foraging periods. Individuals spent less time foraging when forming larger non-vocal aggregations of individuals in late afternoons, and more time foraging when in the mid-range of water depths (300-400m) available in the study area (50-700m). Individuals reduced foraging time by 83% (29-96%) during their first exposure to sonar, but not during killer whale sound playbacks. A relative increase in foraging during repeat sonar exposures indicated habituation or change in response tactic. We discuss the possible adaptive value of these trade-offs in time allocation to reduce individual conflict while maintaining benefits of group living.
The authors would like to thank sponsors, NL Ministry of Defence, NOR Ministry of Defence, U.S. Office of Naval Research (N00014-08-1-0984, N00014-10-1-0355, N00014-14-1-0390), FR Ministry of Defence (DGA; public market no. 15860052), World Wildlife Fund Norway (9E0682), and French Total Foundation and Bleustein-Blanchet Foundation. The statistical development work was supported by a separate grant from the U.S. Office of Naval Research (N00014-12-1-0204), under the project entitled Multi-study OCean acoustics Human effects Analysis (MOCHA).
Fri, 01 Dec 2017 00:00:00 GMThttp://hdl.handle.net/10023/124082017-12-01T00:00:00ZIsojunno, S.Sadykova, D.DeRuiter, S.Curé, C.Visser, F.Thomas, L.Miller, P. J. O.Harris, C. M.Time allocation to different activities and habitats enables individuals to modulate their perceived risks and access to resources, and can reveal important trade-offs between fitness-enhancing activities (e.g., feeding vs. social behavior). Species with long reproductive cycles and high parental investment, such as marine mammals, rely on such behavioral plasticity to cope with rapid environmental change, including anthropogenic stressors. We quantified activity budgets of free-ranging long-finned pilot whales in order to assess individual time trade-offs between foraging and other behaviors in different individual and ecological contexts, and during experimental sound exposures. The experiments included 1-2 and 6-7 kHz naval sonar exposures (a potential anthropogenic stressor), playback of killer whale (a potential predator/competitor) vocalizations, and negative controls. We combined multiple time series data from digital acoustic recording tags (DTAG) as well as group-level social behavior data from visual observations of tagged whales at the surface. The data were classified into near-surface behaviors and dive types (using a hidden Markov model for dive transitions) and aggregated into time budgets. On average, individuals (N=19) spent most of their time (69%) resting and transiting near surface, 21% in shallow dives (depth <40m), and only 10% of their time in deep foraging dives, of which 65% reached a depth 10m from the sea bottom. Individuals in the largest of three body size classes or accompanied by calves tended to spend more time foraging than others. Simultaneous tagging of pairs of individuals showed that up to 50% of the activity budget was synchronized between conspecifics with decreased synchrony during foraging periods. Individuals spent less time foraging when forming larger non-vocal aggregations of individuals in late afternoons, and more time foraging when in the mid-range of water depths (300-400m) available in the study area (50-700m). Individuals reduced foraging time by 83% (29-96%) during their first exposure to sonar, but not during killer whale sound playbacks. A relative increase in foraging during repeat sonar exposures indicated habituation or change in response tactic. We discuss the possible adaptive value of these trade-offs in time allocation to reduce individual conflict while maintaining benefits of group living.A multilevel society of herring-eating killer whales indicates adaptation to prey characteristicshttp://hdl.handle.net/10023/12396
Non-social factors can influence animal social structure. In killer whales (Orcinus orca), fish- versus mammal-eating ecological differences are regarded as key ecological drivers of their multilevel society, including group size, but the potential importance of specific target prey remains unclear. Here, we investigate the social structure of herring-eating killer whales in Iceland and compare it to the described social structures of primarily salmon- and seal-eating populations in the Northeast Pacific, which form stable coherent basic units nested within a hierarchical multilevel society. Using 29023 photographs collected over 6 years, we examined the association patterns of 198 individuals combining clustering, social network structure, and temporal patterns of association analysis. The Icelandic population had largely weak but non-random associations, which were not completely assorted by known ranging patterns. A fission–fusion dynamic of constant and temporary associations was observed but this was not due to permanent units joining. The population-level society was significantly structured but not in a clear hierarchical tier system. Social clusters were highly diverse in complexity and there were indications of subsclusters. There was no indication of dispersal nor strong sex differences in associations. These results indicate that the Icelandic herring-eating killer whale population has a multilevel social structure without clear hierarchical tiers or nested coherent social units, different from other populations of killer whales. We suggest that local ecological context, such as the characteristics of the specific target prey (e.g., predictability, biomass, and density) and subsequent foraging strategies may strongly influence killer whale social association patterns.
This work was supported by the Fundação para a Ciência e a Tecnologia (grant numbers SFSFRH/BD/30303/2006 and SFRH/BD/84714/2012); Icelandic Research Fund (i. Rannsóknasjóđur, grant number 120248402); National Geographic Society Science and Exploration Europe (grant number GEFNE65-12); Office of Naval Research (grant number N00014-08-10984); and a Russell Trust Award from the University of St. Andrews.
Sat, 01 Apr 2017 00:00:00 GMThttp://hdl.handle.net/10023/123962017-04-01T00:00:00ZTavares, Sara B.Samarra, Filipa I. P.Miller, Patrick J. O.Non-social factors can influence animal social structure. In killer whales (Orcinus orca), fish- versus mammal-eating ecological differences are regarded as key ecological drivers of their multilevel society, including group size, but the potential importance of specific target prey remains unclear. Here, we investigate the social structure of herring-eating killer whales in Iceland and compare it to the described social structures of primarily salmon- and seal-eating populations in the Northeast Pacific, which form stable coherent basic units nested within a hierarchical multilevel society. Using 29023 photographs collected over 6 years, we examined the association patterns of 198 individuals combining clustering, social network structure, and temporal patterns of association analysis. The Icelandic population had largely weak but non-random associations, which were not completely assorted by known ranging patterns. A fission–fusion dynamic of constant and temporary associations was observed but this was not due to permanent units joining. The population-level society was significantly structured but not in a clear hierarchical tier system. Social clusters were highly diverse in complexity and there were indications of subsclusters. There was no indication of dispersal nor strong sex differences in associations. These results indicate that the Icelandic herring-eating killer whale population has a multilevel social structure without clear hierarchical tiers or nested coherent social units, different from other populations of killer whales. We suggest that local ecological context, such as the characteristics of the specific target prey (e.g., predictability, biomass, and density) and subsequent foraging strategies may strongly influence killer whale social association patterns.Naval sonar disrupts foraging behaviour in humpback whaleshttp://hdl.handle.net/10023/12394
Modern long-range naval sonars are a potential disturbance for marine mammals and can cause disruption of feeding in cetaceans. We examined the lunge-feeding behaviour of humpback whales Megaptera novaeangliae before, during and after controlled exposure experiments with naval sonar by use of acoustic and motion sensor archival tags attached to each animal. Lunge-feeding by humpback whales entails a strong acceleration to increase speed before engulfing a large volume of prey-laden water, which can be identified by an acoustic signature characterized by a few seconds of high-level flow-noise followed by a rapid reduction, coinciding with a peak in animal acceleration. Over 2 successive seasons, 13 humpback whales were tagged. All were subject to a no-sonar control exposure, and 12 whales were exposed to 2 consecutive sonar exposure sessions, with 1 h between sessions. The first sonar session resulted in an average 68% reduction in lunge rate during exposure compared to pre-exposure, and this reduction was significantly greater than any changes observed during the no-sonar control. During the second sonar session, reduction in lunge rate was 66% during sonar exposure compared to the pre-exposure level, but was not significant compared to the no-sonar control, likely due to a larger inter-individual variability because some individuals appeared to have habituated whereas others had not. Our results indicate that naval sonars operating near humpback whale feeding grounds may lead to reduced foraging and negative impacts on energy balance.
Thu, 29 Dec 2016 00:00:00 GMThttp://hdl.handle.net/10023/123942016-12-29T00:00:00ZSivle, Lise D.Wensveen, Paulus JacobusKvadsheim, PetterLam, Frans-Peter A.Visser, FleurCure, CharlotteHarris, Catriona MTyack, Peter LloydMiller, PatrickModern long-range naval sonars are a potential disturbance for marine mammals and can cause disruption of feeding in cetaceans. We examined the lunge-feeding behaviour of humpback whales Megaptera novaeangliae before, during and after controlled exposure experiments with naval sonar by use of acoustic and motion sensor archival tags attached to each animal. Lunge-feeding by humpback whales entails a strong acceleration to increase speed before engulfing a large volume of prey-laden water, which can be identified by an acoustic signature characterized by a few seconds of high-level flow-noise followed by a rapid reduction, coinciding with a peak in animal acceleration. Over 2 successive seasons, 13 humpback whales were tagged. All were subject to a no-sonar control exposure, and 12 whales were exposed to 2 consecutive sonar exposure sessions, with 1 h between sessions. The first sonar session resulted in an average 68% reduction in lunge rate during exposure compared to pre-exposure, and this reduction was significantly greater than any changes observed during the no-sonar control. During the second sonar session, reduction in lunge rate was 66% during sonar exposure compared to the pre-exposure level, but was not significant compared to the no-sonar control, likely due to a larger inter-individual variability because some individuals appeared to have habituated whereas others had not. Our results indicate that naval sonars operating near humpback whale feeding grounds may lead to reduced foraging and negative impacts on energy balance.Successful suction-cup tagging of a small delphinid species, Stenella attenuata : insights into whistle characteristicshttp://hdl.handle.net/10023/12321
This project was funded by the Office of Naval Research (award number: N000141110612; Program Manager Michael J. Weise), WHOI Marine Mammal Center, and the Sawyer and Penzance Endowed Funds, with additional field time funded by grants through Cascadia Research Collective by the National Oceanographic Partnership Program (through the Alaska SeaLife Center) and the Pacific Islands Fisheries Science Center. PLT acknowledges the support of the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland). MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions.
Thu, 13 Apr 2017 00:00:00 GMThttp://hdl.handle.net/10023/123212017-04-13T00:00:00ZSilva, Tammy L.Aran Mooney, T.Sayigh, Laela S.Baird, Robin W.Tyack, Peter L.Search and foraging behaviors from movement data : a comparison of methodshttp://hdl.handle.net/10023/12295
Search behavior is often used as a proxy for foraging effort within studies of animal movement, despite it being only one part of the foraging process, which also includes prey capture. While methods for validating prey capture exist, many studies rely solely on behavioral annotation of animal movement data to identify search and infer prey capture attempts. However, the degree to which search correlates with prey capture is largely untested. This study applied seven behavioral annotation methods to identify search behavior from GPS tracks of northern gannets (Morus bassanus), and compared outputs to the occurrence of dives recorded by simultaneously deployed time-depth recorders. We tested how behavioral annotation methods vary in their ability to identify search behavior leading to dive events. There was considerable variation in the number of dives occurring within search areas across methods. Hidden Markov models proved to be the most successful, with 81% of all dives occurring within areas identified as search. k-Means clustering and first passage time had the highest rates of dives occurring outside identified search behavior. First passage time and hidden Markov models had the lowest rates of false positives, identifying fewer search areas with no dives. All behavioral annotation methods had advantages and drawbacks in terms of the complexity of analysis and ability to reflect prey capture events while minimizing the number of false positives and false negatives. We used these results, with consideration of analytical difficulty, to provide advice on the most appropriate methods for use where prey capture behavior is not available. This study highlights a need to critically assess and carefully choose a behavioral annotation method suitable for the research question being addressed, or resulting species management frameworks established.
his study was funded by NERC Standard Grant NE/H007466/1. AB is funded by the Irish Research Council (Project ID: GOIPG/2016/503). MJ is funded under Marine Renewable Energy Ireland (MaREI), The SFI Centre for Marine Renewable Energy Research (12/RC/2302), and EW is funded by the NERC (IRF NE/M017990/1).
Thu, 23 Nov 2017 00:00:00 GMThttp://hdl.handle.net/10023/122952017-11-23T00:00:00ZBennison, AshleyBearhop, StuartBodey, Thomas W.Votier, Stephen C.Grecian, W. JamesWakefield, Ewan D.Hamer, Keith C.Jessopp, MarkSearch behavior is often used as a proxy for foraging effort within studies of animal movement, despite it being only one part of the foraging process, which also includes prey capture. While methods for validating prey capture exist, many studies rely solely on behavioral annotation of animal movement data to identify search and infer prey capture attempts. However, the degree to which search correlates with prey capture is largely untested. This study applied seven behavioral annotation methods to identify search behavior from GPS tracks of northern gannets (Morus bassanus), and compared outputs to the occurrence of dives recorded by simultaneously deployed time-depth recorders. We tested how behavioral annotation methods vary in their ability to identify search behavior leading to dive events. There was considerable variation in the number of dives occurring within search areas across methods. Hidden Markov models proved to be the most successful, with 81% of all dives occurring within areas identified as search. k-Means clustering and first passage time had the highest rates of dives occurring outside identified search behavior. First passage time and hidden Markov models had the lowest rates of false positives, identifying fewer search areas with no dives. All behavioral annotation methods had advantages and drawbacks in terms of the complexity of analysis and ability to reflect prey capture events while minimizing the number of false positives and false negatives. We used these results, with consideration of analytical difficulty, to provide advice on the most appropriate methods for use where prey capture behavior is not available. This study highlights a need to critically assess and carefully choose a behavioral annotation method suitable for the research question being addressed, or resulting species management frameworks established.Hooded seal Cystophora cristata foraging areas in the Northeast Atlantic Ocean— investigated using three complementary methodshttp://hdl.handle.net/10023/12288
Identifying environmental characteristics that define the ecological niche of a species is essential to understanding how changes in physical conditions might affect its distribution and other aspects of its ecology. The present study used satellite relay data loggers (SRDLs) to study habitat use by Northeast Atlantic hooded seals (N = 20; 9 adult females, 3 adult males, and 8 juveniles). Three different methods were used in combination to achieve maximum insight regarding key foraging areas for hooded seals in this region, which have decline by 85% in recent decades: 1) first passage time (FPT); 2) vertical transit rate and; 3) change in dive drift rate. Generalized additive mixed models (GAMM) were applied to each method to determine whether specific habitat haracteristics were associated with foraging. Separate models were run for the post-molting and the post-breeding seasons; sex and age classes were included in the GAMMs. All three methods highlighted a few common geographic areas as being important foraging zones; however, there were also some different areas identified by the different methods, which highlights the importance of using multiple indexes when analyzing tracking and diving data to study foraging behavior. Foraging occurred most commonly in relatively shallow areas with high Sea Surface Temperatures (SST), corresponding to continental shelf areas with Atlantic Water masses. All age and sex classes overlapped spatially to some extent, but the different age and sex groups showed differences in the bathymetry of their foraging areas as well as in their vertical use of the water column. When foraging, pups dove in the upper part of the water column in relatively deep areas. Adult females foraged relatively shallowly in deep water areas too, though in shallower areas than pups. Adult males foraged close to the bottom in shallower areas.
This work was funded by the Norwegian Research Council (grant number 176477/S30), within the Norwegian International Polar Year programme and the Norwegian Polar Institute.
Wed, 06 Dec 2017 00:00:00 GMThttp://hdl.handle.net/10023/122882017-12-06T00:00:00ZVacquie-Garcia, JadeLydersen, ChristianBiuw, MartinHaug, ToreFedak, Mike A.Kovacs, Kit M.Identifying environmental characteristics that define the ecological niche of a species is essential to understanding how changes in physical conditions might affect its distribution and other aspects of its ecology. The present study used satellite relay data loggers (SRDLs) to study habitat use by Northeast Atlantic hooded seals (N = 20; 9 adult females, 3 adult males, and 8 juveniles). Three different methods were used in combination to achieve maximum insight regarding key foraging areas for hooded seals in this region, which have decline by 85% in recent decades: 1) first passage time (FPT); 2) vertical transit rate and; 3) change in dive drift rate. Generalized additive mixed models (GAMM) were applied to each method to determine whether specific habitat haracteristics were associated with foraging. Separate models were run for the post-molting and the post-breeding seasons; sex and age classes were included in the GAMMs. All three methods highlighted a few common geographic areas as being important foraging zones; however, there were also some different areas identified by the different methods, which highlights the importance of using multiple indexes when analyzing tracking and diving data to study foraging behavior. Foraging occurred most commonly in relatively shallow areas with high Sea Surface Temperatures (SST), corresponding to continental shelf areas with Atlantic Water masses. All age and sex classes overlapped spatially to some extent, but the different age and sex groups showed differences in the bathymetry of their foraging areas as well as in their vertical use of the water column. When foraging, pups dove in the upper part of the water column in relatively deep areas. Adult females foraged relatively shallowly in deep water areas too, though in shallower areas than pups. Adult males foraged close to the bottom in shallower areas.Sex-related differences in the postmolt distribution of Weddell seals (Leptonychotes weddellii) in the southern Weddell Seahttp://hdl.handle.net/10023/12266
The population of Weddell seals (Leptonychotes weddellii) in the southern Weddell Sea is in a unique position on the continental shelf edge, with vast shelf waters to the south, and deep Southern Ocean to the north. We describe sex-related differences in the winter distribution of this population, from data collected by 20 conductivity-temperature-depth satellite relay data loggers deployed in February 2011 at the end of the annual molt. The regional daily speed was calculated, and a state-space model was used to estimate behavioral states to positions along individuals’ tracks. GLMMs estimated that males and smaller individuals, diving in shallower water, traveled less far per day of deployment (males 14.6 ± 2.26 km/d, females 18.9 ± 2.42 km/d), and males were estimated to dive in shallower water (males 604 ± 382 m, females 1,875 ± 1,458 m). Males and smaller individuals were also estimated to be more resident; males spent an average 83.4% ± 7.7% of their time in a resident behavioral state, compared to females at 74.1% ± 7.1%. This evidence that male and female Weddell seals in the southern Weddell Sea are adopting different strategies has not been shown elsewhere along their circumpolar distribution.
Funding: NERC grants NE/G014833/1 (MF) and NE/G014086/1 (KWN).
Sun, 01 Apr 2018 00:00:00 GMThttp://hdl.handle.net/10023/122662018-04-01T00:00:00ZLangley, IzzyFedak, MikeNicholls, KeithBoehme, LarsThe population of Weddell seals (Leptonychotes weddellii) in the southern Weddell Sea is in a unique position on the continental shelf edge, with vast shelf waters to the south, and deep Southern Ocean to the north. We describe sex-related differences in the winter distribution of this population, from data collected by 20 conductivity-temperature-depth satellite relay data loggers deployed in February 2011 at the end of the annual molt. The regional daily speed was calculated, and a state-space model was used to estimate behavioral states to positions along individuals’ tracks. GLMMs estimated that males and smaller individuals, diving in shallower water, traveled less far per day of deployment (males 14.6 ± 2.26 km/d, females 18.9 ± 2.42 km/d), and males were estimated to dive in shallower water (males 604 ± 382 m, females 1,875 ± 1,458 m). Males and smaller individuals were also estimated to be more resident; males spent an average 83.4% ± 7.7% of their time in a resident behavioral state, compared to females at 74.1% ± 7.1%. This evidence that male and female Weddell seals in the southern Weddell Sea are adopting different strategies has not been shown elsewhere along their circumpolar distribution.In-situ observations using tagged animalshttp://hdl.handle.net/10023/12257
Marine mammals help gather information on some of the harshest environments on the planet, through the use of miniaturized ocean sensors glued on their fur. Since 2004, hundreds of diving marine animals, mainly Antarctic and Arctic seals, have been fitted with a new generation of Argos tags developed by the Sea Mammal Research Unit of the University of St Andrews in Scotland, UK. These tags investigate the at-sea ecology of these animals while simultaneously collecting valuable oceanographic data. Some of the study species travel thousands of kilometres continuously diving to great depths (up to 2100 m). The resulting data are now freely available to the global scientific community at http://www.meop.net. Despite great progress in their reliability and data accuracy, the current generation of loggers while approaching standard ARGO quality specifications have yet to match them. Yet, improvements are underway; they involve updating the technology, implementing a more systematic phase of calibration and taking benefit of the recently acquired knowledge on the dynamical response of sensors. Together these efforts are rapidly transforming animal tagging into one of the most important sources of oceanographic data in polar regions and in many coastal areas.
Tue, 21 Feb 2017 00:00:00 GMThttp://hdl.handle.net/10023/122572017-02-21T00:00:00ZRoquet, FabienBoehme, LarsBester, MarthanBornemann, HorstBrasseur, SophieCharrassin, Jean-BenoitCosta, DanielFedak, Michael AndreGuinet, ChristopheHall, Ailsa JaneHarcourt, RobertHindell, MarkKovacs, Kit M.Lea, Mary-AnneLovell, PhilipLowther, AndrewLydersen, ChristianMcMahon, ClivePicard, BaptisteReverdin, GillesVincent, CécileMarine mammals help gather information on some of the harshest environments on the planet, through the use of miniaturized ocean sensors glued on their fur. Since 2004, hundreds of diving marine animals, mainly Antarctic and Arctic seals, have been fitted with a new generation of Argos tags developed by the Sea Mammal Research Unit of the University of St Andrews in Scotland, UK. These tags investigate the at-sea ecology of these animals while simultaneously collecting valuable oceanographic data. Some of the study species travel thousands of kilometres continuously diving to great depths (up to 2100 m). The resulting data are now freely available to the global scientific community at http://www.meop.net. Despite great progress in their reliability and data accuracy, the current generation of loggers while approaching standard ARGO quality specifications have yet to match them. Yet, improvements are underway; they involve updating the technology, implementing a more systematic phase of calibration and taking benefit of the recently acquired knowledge on the dynamical response of sensors. Together these efforts are rapidly transforming animal tagging into one of the most important sources of oceanographic data in polar regions and in many coastal areas.Modelling harbour seal movementshttp://hdl.handle.net/10023/12185
Wed, 11 Oct 2017 00:00:00 GMThttp://hdl.handle.net/10023/121852017-10-11T00:00:00ZMcConnell, Bernie JSmout, Sophie CarolineWu, MickRapid changes in Atlantic grey seal milk from birth to weaning – immune factors and indicators of metabolic strainhttp://hdl.handle.net/10023/12157
True seals have the shortest lactation periods of any group of placental mammal. Most are capital breeders that undergo short, intense lactations, during which they fast while transferring substantial proportions of their body reserves to their pups, which they then abruptly wean. Milk was collected from Atlantic grey seals (Halichoerus grypus) periodically from birth until near weaning. Milk protein profiles matured within 24 hours or less, indicating the most rapid transition from colostrum to mature phase lactation yet observed. There was an unexpected persistence of immunoglobulin G almost until weaning, potentially indicating prolonged trans-intestinal transfer of IgG. Among components of innate immune protection were found fucosyllactose and siallylactose that are thought to impede colonisation by pathogens and encourage an appropriate milk-digestive and protective gut microbiome. These oligosaccharides decreased from early lactation to almost undetectable levels by weaning. Taurine levels were initially high, then fell, possibly indicative of taurine dependency in seals, and progressive depletion of maternal reserves. Metabolites that signal changes in the mother’s metabolism of fats, such as nicotinamide and derivatives, rose from virtual absence, and acetylcarnitines fell. It is therefore possible that indicators of maternal metabolic strain exist that signal the imminence of weaning.
Thu, 23 Nov 2017 00:00:00 GMThttp://hdl.handle.net/10023/121572017-11-23T00:00:00ZLowe, Amanda D.Bawazeer, SamiWatson, David G.McGill, SuzanneBurchmore, Richard J.S.Pomeroy, PatrickKennedy, Malcolm W.True seals have the shortest lactation periods of any group of placental mammal. Most are capital breeders that undergo short, intense lactations, during which they fast while transferring substantial proportions of their body reserves to their pups, which they then abruptly wean. Milk was collected from Atlantic grey seals (Halichoerus grypus) periodically from birth until near weaning. Milk protein profiles matured within 24 hours or less, indicating the most rapid transition from colostrum to mature phase lactation yet observed. There was an unexpected persistence of immunoglobulin G almost until weaning, potentially indicating prolonged trans-intestinal transfer of IgG. Among components of innate immune protection were found fucosyllactose and siallylactose that are thought to impede colonisation by pathogens and encourage an appropriate milk-digestive and protective gut microbiome. These oligosaccharides decreased from early lactation to almost undetectable levels by weaning. Taurine levels were initially high, then fell, possibly indicative of taurine dependency in seals, and progressive depletion of maternal reserves. Metabolites that signal changes in the mother’s metabolism of fats, such as nicotinamide and derivatives, rose from virtual absence, and acetylcarnitines fell. It is therefore possible that indicators of maternal metabolic strain exist that signal the imminence of weaning.Cognitive control of heart rate in diving harbor porpoiseshttp://hdl.handle.net/10023/12145
Marine mammals have adapted to forage while holding their breath in a suite of aquatic habitats from shallow rivers to deep oceans. The key to tolerate such extensive apnea is the dive response, which comprises bradycardia and peripheral vasoconstriction. Although initially considered an all-or-nothing reflex [1] , numerous studies on freely diving marine mammals have revealed substantial dynamics of the dive response to meet the impending dive demands of depth, duration and exercise [2] . Such adjustments are not only autonomic responses, but are under acute cognitive control in pinnipeds [3] living amphibiously on land and in water. The fully aquatic cetaceans would similarly benefit from cognitive cardiovascular control; however, even though they have exercise-modulated diving bradycardia [2] and full voluntary control of their respiratory system to such extent that even mild anesthesia often leads to asphyxiation [4] , cognitive cardiovascular control has never been demonstrated for this large group of marine mammals. To address this, we tested the hypothesis that porpoises modulate bradycardia according to anticipated dive duration. Two harbor porpoises, instrumented with ECG recording tags, were trained to perform 20- and 80-second stationary dives, during which they adjusted bradycardia to the anticipated duration, demonstrating cognitive control of their dive response.
M.J. was funded by the Marine Alliance for Science and Technology, Scotland, and by a Marie Curie Career Integration Grant.
Mon, 21 Nov 2016 00:00:00 GMThttp://hdl.handle.net/10023/121452016-11-21T00:00:00ZElmegaard, SiriJohnson, MarkMadsen, PeterMcDonald, BirgitteMarine mammals have adapted to forage while holding their breath in a suite of aquatic habitats from shallow rivers to deep oceans. The key to tolerate such extensive apnea is the dive response, which comprises bradycardia and peripheral vasoconstriction. Although initially considered an all-or-nothing reflex [1] , numerous studies on freely diving marine mammals have revealed substantial dynamics of the dive response to meet the impending dive demands of depth, duration and exercise [2] . Such adjustments are not only autonomic responses, but are under acute cognitive control in pinnipeds [3] living amphibiously on land and in water. The fully aquatic cetaceans would similarly benefit from cognitive cardiovascular control; however, even though they have exercise-modulated diving bradycardia [2] and full voluntary control of their respiratory system to such extent that even mild anesthesia often leads to asphyxiation [4] , cognitive cardiovascular control has never been demonstrated for this large group of marine mammals. To address this, we tested the hypothesis that porpoises modulate bradycardia according to anticipated dive duration. Two harbor porpoises, instrumented with ECG recording tags, were trained to perform 20- and 80-second stationary dives, during which they adjusted bradycardia to the anticipated duration, demonstrating cognitive control of their dive response.Vocal foragers and silent crowds : context-dependent vocal variation in Northeast Atlantic long-finned pilot whaleshttp://hdl.handle.net/10023/12141
Vocalisations form a key component of the social interactions and foraging behaviour of toothed whales. We investigated changes in calling and echolocation behaviour of long-finned pilot whales between foraging and non-foraging periods, by combining acoustic recordings and diving depth data from tagged individuals with concurrent surface observations on social behaviour of their group. The pilot whales showed marked vocal variation, specific to foraging and social context. During periods of foraging, pilot whales showed more vocal activity than during non-foraging periods (rest, travel). In addition to the expected increase in echolocation activity, call rates also increased, suggesting that pilot whales communicate more during foraging. Furthermore, calls with multiple inflections occurred more often immediately before and after foraging dives and during the early descent and late ascent phases of foraging dives. However, these calls were almost never detected at diving depths of the tagged whale beyond 350 m. Calls with no or few inflections were produced at all times, irrespective of diving depth of the tagged whale. We discuss possible explanations for the distinct vocal variation associated with foraging periods. In addition, during non-foraging periods, the pilot whales were found to be more silent (no calling or echolocation) in larger, more closely spaced groups. This indicates that increased levels of social cohesion may release the need to stay in touch acoustically. Significance statement: Social toothed whales rely on vocalisations to find prey and interact with conspecifics. Species are often highly vocal and can have elaborate call repertoires. However, it often remains unclear how their repertoire use correlates to specific social and behavioural contexts, which is vital to understand toothed whale foraging strategies and sociality. Combining on-animal tag recordings of diving and acoustic behaviour with observations of social behaviour, we found that pilot whales produce more calls during foraging than during non-foraging periods. Moreover, highly inflected calls were closely associated to the periods around and during foraging dives. This indicates enhanced communication during foraging, which may, for example, enable relocation of conspecifics or sharing of information. Whales reduced their vocal activity (calling and echolocation) at increased levels of social cohesion, indicating that in certain behavioural contexts, closer association (i.e. more closely spaced) may release the need to stay in touch acoustically.
This study was financially supported by the US Office of Naval Research, The Netherlands Ministry of Defence, the Norwegian Research Council and the Norwegian Ministry of Defence.
Fri, 01 Dec 2017 00:00:00 GMThttp://hdl.handle.net/10023/121412017-12-01T00:00:00ZVisser, FleurKok, Annebelle C.M.Oudejans, Machiel G.Scott-Hayward, Lindesay A.S.DeRuiter, Stacy L.Alves, Ana C.Antunes, Ricardo N.Isojunno, SaanaPierce, Graham J.Slabbekoorn, HansHuisman, JefMiller, Patrick J.O.Vocalisations form a key component of the social interactions and foraging behaviour of toothed whales. We investigated changes in calling and echolocation behaviour of long-finned pilot whales between foraging and non-foraging periods, by combining acoustic recordings and diving depth data from tagged individuals with concurrent surface observations on social behaviour of their group. The pilot whales showed marked vocal variation, specific to foraging and social context. During periods of foraging, pilot whales showed more vocal activity than during non-foraging periods (rest, travel). In addition to the expected increase in echolocation activity, call rates also increased, suggesting that pilot whales communicate more during foraging. Furthermore, calls with multiple inflections occurred more often immediately before and after foraging dives and during the early descent and late ascent phases of foraging dives. However, these calls were almost never detected at diving depths of the tagged whale beyond 350 m. Calls with no or few inflections were produced at all times, irrespective of diving depth of the tagged whale. We discuss possible explanations for the distinct vocal variation associated with foraging periods. In addition, during non-foraging periods, the pilot whales were found to be more silent (no calling or echolocation) in larger, more closely spaced groups. This indicates that increased levels of social cohesion may release the need to stay in touch acoustically. Significance statement: Social toothed whales rely on vocalisations to find prey and interact with conspecifics. Species are often highly vocal and can have elaborate call repertoires. However, it often remains unclear how their repertoire use correlates to specific social and behavioural contexts, which is vital to understand toothed whale foraging strategies and sociality. Combining on-animal tag recordings of diving and acoustic behaviour with observations of social behaviour, we found that pilot whales produce more calls during foraging than during non-foraging periods. Moreover, highly inflected calls were closely associated to the periods around and during foraging dives. This indicates enhanced communication during foraging, which may, for example, enable relocation of conspecifics or sharing of information. Whales reduced their vocal activity (calling and echolocation) at increased levels of social cohesion, indicating that in certain behavioural contexts, closer association (i.e. more closely spaced) may release the need to stay in touch acoustically.Lack of behavioural responses of humpback whales (Megaptera novaeangliae) indicate limited effectiveness of sonar mitigationhttp://hdl.handle.net/10023/12116
Exposure to underwater sound can cause permanent hearing loss and other physiological effects in marine animals. To reduce this risk, naval sonars are sometimes gradually increased in intensity at the start of transmission (‘ramp-up’). Here, we conducted experiments in which tagged humpback whales were approached with a ship to test whether a sonar operation preceded by ramp-up reduced three risk indicators – maximum sound pressure level (SPLmax), cumulative sound exposure level (SELcum) and minimum source–whale range (Rmin) – compared with a sonar operation not preceded by ramp-up. Whales were subject to one no-sonar control session and either two successive ramp-up sessions (RampUp1, RampUp2) or a ramp-up session (RampUp1) and a full-power session (FullPower). Full-power sessions were conducted only twice; for other whales we used acoustic modelling that assumed transmission of the full-power sequence during their no-sonar control. Averaged over all whales, risk indicators in RampUp1 (n=11) differed significantly from those in FullPower (n=12) by −3.0 dB (SPLmax), −2.0 dB (SELcum) and +168 m (Rmin), but not significantly from those in RampUp2 (n=9). Only five whales in RampUp1, four whales in RampUp2 and none in FullPower or control sessions avoided the sound source. For RampUp1, we found statistically significant differences in risk indicators between whales that avoided the sonar and whales that did not: −4.7 dB (SPLmax), −3.4 dB (SELcum) and +291 m (Rmin). In contrast, for RampUp2, these differences were smaller and not significant. This study suggests that sonar ramp-up has a positive but limited mitigative effect for humpback whales overall, but that ramp-up can reduce the risk of harm more effectively in situations when animals are more responsive and likely to avoid the sonar, e.g. owing to novelty of the stimulus, when they are in the path of an approaching sonar ship.
Funding: Natural Environment Research Council [NE/J500276/1 to P.J.W]; and the MASTS (The Marine Alliance for Science and Technology for Scotland) pooling initiative to P.L.T. MASTS is funded by the Scottish Funding Council [HR09011] and contributing institutions.
Wed, 15 Nov 2017 00:00:00 GMThttp://hdl.handle.net/10023/121162017-11-15T00:00:00ZWensveen, Paul J.Kvadsheim, Petter H.Lam, Frans-Peter A.von Benda-Beckmann, Alexander M.Sivle, Lise D.Visser, FleurCuré, CharlotteTyack, Peter L.Miller, Patrick J. O.Exposure to underwater sound can cause permanent hearing loss and other physiological effects in marine animals. To reduce this risk, naval sonars are sometimes gradually increased in intensity at the start of transmission (‘ramp-up’). Here, we conducted experiments in which tagged humpback whales were approached with a ship to test whether a sonar operation preceded by ramp-up reduced three risk indicators – maximum sound pressure level (SPLmax), cumulative sound exposure level (SELcum) and minimum source–whale range (Rmin) – compared with a sonar operation not preceded by ramp-up. Whales were subject to one no-sonar control session and either two successive ramp-up sessions (RampUp1, RampUp2) or a ramp-up session (RampUp1) and a full-power session (FullPower). Full-power sessions were conducted only twice; for other whales we used acoustic modelling that assumed transmission of the full-power sequence during their no-sonar control. Averaged over all whales, risk indicators in RampUp1 (n=11) differed significantly from those in FullPower (n=12) by −3.0 dB (SPLmax), −2.0 dB (SELcum) and +168 m (Rmin), but not significantly from those in RampUp2 (n=9). Only five whales in RampUp1, four whales in RampUp2 and none in FullPower or control sessions avoided the sound source. For RampUp1, we found statistically significant differences in risk indicators between whales that avoided the sonar and whales that did not: −4.7 dB (SPLmax), −3.4 dB (SELcum) and +291 m (Rmin). In contrast, for RampUp2, these differences were smaller and not significant. This study suggests that sonar ramp-up has a positive but limited mitigative effect for humpback whales overall, but that ramp-up can reduce the risk of harm more effectively in situations when animals are more responsive and likely to avoid the sonar, e.g. owing to novelty of the stimulus, when they are in the path of an approaching sonar ship.Seals and Wild Salmon Fisheries: Interim Reporthttp://hdl.handle.net/10023/12017
Tue, 07 Nov 2017 00:00:00 GMThttp://hdl.handle.net/10023/120172017-11-07T00:00:00ZHarris, RobertNorthridge, Simon PatrickA path reconstruction method integrating dead-reckoning and position fixes applied to humpback whaleshttp://hdl.handle.net/10023/11976
BACKGROUND: Detailed information about animal location and movement is often crucial in studies of natural behaviour and how animals respond to anthropogenic activities. Dead-reckoning can be used to infer such detailed information, but without additional positional data this method results in uncertainty that grows with time. Combining dead-reckoning with new Fastloc-GPS technology should provide good opportunities for reconstructing georeferenced fine-scale tracks, and should be particularly useful for marine animals that spend most of their time under water. We developed a computationally efficient, Bayesian state-space modelling technique to estimate humpback whale locations through time, integrating dead-reckoning using on-animal sensors with measurements of whale locations using on-animal Fastloc-GPS and visual observations. Positional observation models were based upon error measurements made during calibrations. RESULTS: High-resolution 3-dimensional movement tracks were produced for 13 whales using a simple process model in which errors caused by water current movements, non-location sensor errors, and other dead-reckoning errors were accumulated into a combined error term. Positional uncertainty quantified by the track reconstruction model was much greater for tracks with visual positions and few or no GPS positions, indicating a strong benefit to using Fastloc-GPS for track reconstruction. Compared to tracks derived only from position fixes, the inclusion of dead-reckoning data greatly improved the level of detail in the reconstructed tracks of humpback whales. Using cross-validation, a clear improvement in the predictability of out-of-set Fastloc-GPS data was observed compared to more conventional track reconstruction methods. Fastloc-GPS observation errors during calibrations were found to vary by number of GPS satellites received and by orthogonal dimension analysed; visual observation errors varied most by distance to the whale. CONCLUSIONS: By systematically accounting for the observation errors in the position fixes, our model provides a quantitative estimate of location uncertainty that can be appropriately incorporated into analyses of animal movement. This generic method has potential application for a wide range of marine animal species and data recording systems.
PW received a PhD studentship with matched funding from The Netherlands Ministry of Defence (administered by TNO) and the UK Natural Environment Research Council (NE/J500276/1). The 3S2 project was funded by the US Office of Naval Research (N00014-10-1-0355), the Norwegian Ministry of Defence, and The Netherlands Ministry of Defence. Part of this work was supported by the Multi-study Ocean acoustics Human effects Analysis (MOCHA) project funded by the US Office of Naval Research (N00014-12-1-0204).
Mon, 21 Sep 2015 00:00:00 GMThttp://hdl.handle.net/10023/119762015-09-21T00:00:00ZWensveen, Paul J.Thomas, LenMiller, Patrick J OBACKGROUND: Detailed information about animal location and movement is often crucial in studies of natural behaviour and how animals respond to anthropogenic activities. Dead-reckoning can be used to infer such detailed information, but without additional positional data this method results in uncertainty that grows with time. Combining dead-reckoning with new Fastloc-GPS technology should provide good opportunities for reconstructing georeferenced fine-scale tracks, and should be particularly useful for marine animals that spend most of their time under water. We developed a computationally efficient, Bayesian state-space modelling technique to estimate humpback whale locations through time, integrating dead-reckoning using on-animal sensors with measurements of whale locations using on-animal Fastloc-GPS and visual observations. Positional observation models were based upon error measurements made during calibrations. RESULTS: High-resolution 3-dimensional movement tracks were produced for 13 whales using a simple process model in which errors caused by water current movements, non-location sensor errors, and other dead-reckoning errors were accumulated into a combined error term. Positional uncertainty quantified by the track reconstruction model was much greater for tracks with visual positions and few or no GPS positions, indicating a strong benefit to using Fastloc-GPS for track reconstruction. Compared to tracks derived only from position fixes, the inclusion of dead-reckoning data greatly improved the level of detail in the reconstructed tracks of humpback whales. Using cross-validation, a clear improvement in the predictability of out-of-set Fastloc-GPS data was observed compared to more conventional track reconstruction methods. Fastloc-GPS observation errors during calibrations were found to vary by number of GPS satellites received and by orthogonal dimension analysed; visual observation errors varied most by distance to the whale. CONCLUSIONS: By systematically accounting for the observation errors in the position fixes, our model provides a quantitative estimate of location uncertainty that can be appropriately incorporated into analyses of animal movement. This generic method has potential application for a wide range of marine animal species and data recording systems.Evidence suggests vocal production learning in a cross-fostered Risso’s dolphin (Grampus griseus)http://hdl.handle.net/10023/11883
Vocal learning is a rare skill in mammals, and we have limited information about the contexts in which they use it. Previous studies suggested that cetaceans in general are skilled at imitating sounds, but only few species have been studied to date. To expand this investigation to another species and to investigate the possible influence of the social environment on vocal learning, we studied the whistle repertoire of a female Risso’s dolphin (Grampus griseus) that was stranded at an early age and was subsequently raised in a group of bottlenose dolphins (Tursiops truncatus). We show that this cross-fostered animal produced vocal signals more akin to those of its Tursiops poolmates than those of Risso’s dolphins in the wild. This is one of very few systematic cross-fostering studies in cetaceans and the first to suggest vocal production learning in the Risso’s dolphin. Our findings also suggest that social experience is a major factor in the development of the vocal repertoire in this species.
Fri, 01 Jul 2016 00:00:00 GMThttp://hdl.handle.net/10023/118832016-07-01T00:00:00ZFavaro, LivioNeves, SilvanaFurlati, StefanoPessani, DanielaMartin, VidalJanik, Vincent M.Vocal learning is a rare skill in mammals, and we have limited information about the contexts in which they use it. Previous studies suggested that cetaceans in general are skilled at imitating sounds, but only few species have been studied to date. To expand this investigation to another species and to investigate the possible influence of the social environment on vocal learning, we studied the whistle repertoire of a female Risso’s dolphin (Grampus griseus) that was stranded at an early age and was subsequently raised in a group of bottlenose dolphins (Tursiops truncatus). We show that this cross-fostered animal produced vocal signals more akin to those of its Tursiops poolmates than those of Risso’s dolphins in the wild. This is one of very few systematic cross-fostering studies in cetaceans and the first to suggest vocal production learning in the Risso’s dolphin. Our findings also suggest that social experience is a major factor in the development of the vocal repertoire in this species.Come dine with me : food-associated social signalling in wild bottlenose dolphins (Tursiops truncatus)http://hdl.handle.net/10023/11882
Food-related signalling is widespread in the animal kingdom with some food-associated vocalizations considered functionally referential. Food calls can, however, vary greatly in the type of information they convey. Thus, there are a multitude of purposes for which food calls are used, including social recruitment, caller spacing, the indication of type, quantity, quality, divisibility of food, the caller’s hunger level and even as tools to manipulate prey behaviour. Yet little work has focused on the social aspect of food calling in animals. We investigated the association of social signals in wild bottlenose dolphins with foraging behaviour where context-specific food-associated calls are commonly produced. Our data showed that specific social signals were significantly correlated with food call production and these calls rarely occurred in the absence of food calls. We suggest that animals are sharing additional information on the food patch itself with their social affiliates.
The project was funded by a BBSRC Studentship to S.L.K., and a Royal Society University Research Fellowship and a Fellowship of the Wissenschaftskolleg Berlin to V.M.J.
Wed, 01 Jul 2015 00:00:00 GMThttp://hdl.handle.net/10023/118822015-07-01T00:00:00ZKing, Stephanie LauraJanik, Vincent M.Food-related signalling is widespread in the animal kingdom with some food-associated vocalizations considered functionally referential. Food calls can, however, vary greatly in the type of information they convey. Thus, there are a multitude of purposes for which food calls are used, including social recruitment, caller spacing, the indication of type, quantity, quality, divisibility of food, the caller’s hunger level and even as tools to manipulate prey behaviour. Yet little work has focused on the social aspect of food calling in animals. We investigated the association of social signals in wild bottlenose dolphins with foraging behaviour where context-specific food-associated calls are commonly produced. Our data showed that specific social signals were significantly correlated with food call production and these calls rarely occurred in the absence of food calls. We suggest that animals are sharing additional information on the food patch itself with their social affiliates.Physiological constraints and energetic costs of diving behaviour in marine mammals : a review of studies using trained Steller sea lions diving in the open oceanhttp://hdl.handle.net/10023/11765
Marine mammals are characterized as having physiological specializations that maximize the use of oxygen stores to prolong time spent under water. However, it has been difficult to undertake the requisite controlled studies to determine the physiological limitations and trade-offs that marine mammals face while diving in the wild under varying environmental and nutritional conditions. For the past decade, Steller sea lions (Eumetopias jubatus) trained to swim and dive in the open ocean away from the physical confines of pools participated in studies that investigated the interactions between diving behaviour, energetic costs, physiological constraints, and prey availability. Many of these studies measured the cost of diving to understand how it varies with behaviour and environmental and physiological conditions. Collectively, these studies show that the type of diving (dive bouts or single dives), the level of underwater activity, the depth and duration of dives, and the nutritional status and physical condition of the animal affect the cost of diving and foraging. They show that dive depth, dive and surface duration, and the type of dive result in physiological adjustments (heart rate, gas exchange) that may be independent of energy expenditure. They also demonstrate that changes in prey abundance and nutritional status cause sea lions to alter the balance between time spent at the surface acquiring oxygen (and offloading CO2 and other metabolic by-products) and time spent at depth acquiring prey. These new insights into the physiological basis of diving behaviour further our understanding of the potential scope for behavioural responses of marine mammals to environmental changes, the energetic significance of these adjustments, and the consequences of approaching physiological limits.
The research was funded through a number of sources, including grants provided by the Natural Sciences and Engineering Research Council (Canada) and from the US National Oceanic and Atmospheric Administration to the North Pacific Universities Marine Mammal Research Consortium through the North Pacific Marine Science Foundation.
Sun, 01 Jan 2017 00:00:00 GMThttp://hdl.handle.net/10023/117652017-01-01T00:00:00ZRosen, DavidHindle, AllysonFahlman, AndreasGerlinsky, CarlingGoundie, ElizabethHastie, Gordon DrummondVolpov, BethTrites, AndrewMarine mammals are characterized as having physiological specializations that maximize the use of oxygen stores to prolong time spent under water. However, it has been difficult to undertake the requisite controlled studies to determine the physiological limitations and trade-offs that marine mammals face while diving in the wild under varying environmental and nutritional conditions. For the past decade, Steller sea lions (Eumetopias jubatus) trained to swim and dive in the open ocean away from the physical confines of pools participated in studies that investigated the interactions between diving behaviour, energetic costs, physiological constraints, and prey availability. Many of these studies measured the cost of diving to understand how it varies with behaviour and environmental and physiological conditions. Collectively, these studies show that the type of diving (dive bouts or single dives), the level of underwater activity, the depth and duration of dives, and the nutritional status and physical condition of the animal affect the cost of diving and foraging. They show that dive depth, dive and surface duration, and the type of dive result in physiological adjustments (heart rate, gas exchange) that may be independent of energy expenditure. They also demonstrate that changes in prey abundance and nutritional status cause sea lions to alter the balance between time spent at the surface acquiring oxygen (and offloading CO2 and other metabolic by-products) and time spent at depth acquiring prey. These new insights into the physiological basis of diving behaviour further our understanding of the potential scope for behavioural responses of marine mammals to environmental changes, the energetic significance of these adjustments, and the consequences of approaching physiological limits.Shipping noise in a dynamic sea : a case study of grey seals in the Celtic Seahttp://hdl.handle.net/10023/11731
Shipping noise is a threat to marine wildlife. Grey seals are benthic foragers, and thus experience acoustic noise throughout the water column, which makes them a good model species for a case study of the potential impacts of shipping noise. We used ship track data from the Celtic Sea, seal track data and a coupled ocean-acoustic modelling system to assess the noise exposure of grey seals along their tracks. It was found that the animals experience step changes in sound levels up to ~ 20 dB at a frequency of 125 Hz, and ~ 10 dB on average over 10–1000 Hz when they dive through the thermocline, particularly during summer. Our results showed large seasonal differences in the noise level experienced by the seals. These results reveal the actual noise exposure by the animals and could help in marine spatial planning.
This study was supported by the EU (via PERSEUS grant FP7-OCEAN-2011-287600 and MyOcean SPA.2011.1.5-01 grant 283367). In addition, C.B. Embling was supported by the 2014 SoMSE Plymouth University Small (grant number 2014-SoMSE) research grant. D.J.F. Russell and D. Thompson were supported by the National Capability funding from the Natural Environment Research Council to the Sea Mammal Research Unit (grant no. SMRU1001). C. Vincent was supported by the Parc naturel marin d'Iroise and Région Poitou – Charentes (grant number 782423).
Sun, 15 Jan 2017 00:00:00 GMThttp://hdl.handle.net/10023/117312017-01-15T00:00:00ZChen, F.Shapiro, G. I.Bennett, K. A.Ingram, S. N.Thompson, D.Vincent, C.Russell, D. J. F.Embling, C. B.Shipping noise is a threat to marine wildlife. Grey seals are benthic foragers, and thus experience acoustic noise throughout the water column, which makes them a good model species for a case study of the potential impacts of shipping noise. We used ship track data from the Celtic Sea, seal track data and a coupled ocean-acoustic modelling system to assess the noise exposure of grey seals along their tracks. It was found that the animals experience step changes in sound levels up to ~ 20 dB at a frequency of 125 Hz, and ~ 10 dB on average over 10–1000 Hz when they dive through the thermocline, particularly during summer. Our results showed large seasonal differences in the noise level experienced by the seals. These results reveal the actual noise exposure by the animals and could help in marine spatial planning.Exposure of harbour seals (Phoca vitulina) to Brucella in declining populations across Scotlandhttp://hdl.handle.net/10023/11719
Since 2000 there have been major declines in the abundance of Scottish harbour seals (Phoca vitulina). The causes of the declines remain uncertain. The aim of this study was to establish the extent to which the seals in the regions of greatest decline have been exposed to Brucella, a bacterial pathogen that causes reproductive failure in terrestrial mammalian hosts. Tissues from dead seals collected between 1992 and 2013 were cultured for Brucella (n=150). Serum samples collected from live capture-released seals (n=343) between 1997 and 2012 were tested for Brucella antibodies using the Rose Bengal plate agglutination test (RBT) and a competitive Enzyme-Linked Immunosorbent Assay (ELISA). 16% of seals cultured had Brucella isolated from one or more tissues but there were no pathological signs of infection. The cELISA results were more sensitive than the RBT results showing that overall, 25.4% of seals were seropositive with the highest seroprevalence in juveniles. As there was no evidence of either a higher seroprevalence, or higher circulating antibody levels in seropositive animals in the areas with the greatest declines, it was concluded that Brucella infection is likely not a major contributing factor to recent declines. However, the consistently high proportion of seals exposed to Brucella indicates possible endemicity in these populations, likely due to B. pinnipedialis, which has demonstrated a preference for pinniped hosts. Importantly, given the close proximity between seals, humans and livestock in many areas, there is the potential for cross-species infections.
The authors acknowledge the NERC National Capability Funding grant number SMRU 10001 for the funding
Wed, 20 Sep 2017 00:00:00 GMThttp://hdl.handle.net/10023/117192017-09-20T00:00:00ZKershaw, Joanna LouiseStubberfield, Emma J.Foster, GeoffreyBrownlow, AndrewHall, Ailsa JanePerrett, Lorraine L.Since 2000 there have been major declines in the abundance of Scottish harbour seals (Phoca vitulina). The causes of the declines remain uncertain. The aim of this study was to establish the extent to which the seals in the regions of greatest decline have been exposed to Brucella, a bacterial pathogen that causes reproductive failure in terrestrial mammalian hosts. Tissues from dead seals collected between 1992 and 2013 were cultured for Brucella (n=150). Serum samples collected from live capture-released seals (n=343) between 1997 and 2012 were tested for Brucella antibodies using the Rose Bengal plate agglutination test (RBT) and a competitive Enzyme-Linked Immunosorbent Assay (ELISA). 16% of seals cultured had Brucella isolated from one or more tissues but there were no pathological signs of infection. The cELISA results were more sensitive than the RBT results showing that overall, 25.4% of seals were seropositive with the highest seroprevalence in juveniles. As there was no evidence of either a higher seroprevalence, or higher circulating antibody levels in seropositive animals in the areas with the greatest declines, it was concluded that Brucella infection is likely not a major contributing factor to recent declines. However, the consistently high proportion of seals exposed to Brucella indicates possible endemicity in these populations, likely due to B. pinnipedialis, which has demonstrated a preference for pinniped hosts. Importantly, given the close proximity between seals, humans and livestock in many areas, there is the potential for cross-species infections.Spatio-temporal variation in click production rates of beaked whales : implications for passive acoustic density estimationhttp://hdl.handle.net/10023/11712
Passive acoustic monitoring has become an increasingly prevalent tool for estimating density of marine mammals, such as beaked whales, which vocalize often but are difficult to survey visually. Counts of acoustic cues (e.g., vocalizations), when corrected for detection probability, can be translated into animal density estimates by applying an individual cue production rate multiplier. It is essential to understand variation in these rates to avoid biased estimates. The most direct way to measure cue production rate is with animal-mounted acoustic recorders. This study utilized data from sound recording tags deployed on Blainville's (Mesoplodon densirostris, 19 deployments) and Cuvier's (Ziphius cavirostris, 16 deployments) beaked whales, in two locations per species, to explore spatial and temporal variation in click production rates. No spatial or temporal variation was detected within the average click production rate of Blainville's beaked whales when calculated over dive cycles (including silent periods between dives); however, spatial variation was detected when averaged only over vocal periods. Cuvier's beaked whales exhibited significant spatial and temporal variation in click production rates within vocal periods and when silent periods were included. This evidence of variation emphasizes the need to utilize appropriate cue production rates when estimating density from passive acoustic data.
T.A.M. was funded under Grant No. N000141010382 from the Office of Naval Research (LATTE project) and thanks support by CEAUL (funded by FCT - Fundação para a Ciência e a Tecnologia, Portugal, through the project UID/MAT/00006/2013). M.P.J. was funded by a Marie Curie Career Integration Grant and M.P.J. and P.L.T. were funded by MASTS (The Marine Alliance for Science and Technology for Scotland, a research pooling initiative funded by the Scottish Funding Council under grant HR09011 and contributing institutions). L.S.H. thanks the BRS Bahamas team that helped collect the Bahamas data, and A. Bocconcelli. D.H. and L.T. were funded by the Office of Naval Research (Award No. N00014-14-1-0394). N.A.S. was funded by an EU-Horizon 2020 Marie Slodowska Curie fellowship (project ECOSOUND). DTAG data in the Canary Islands were collected with funds from the U.S. Office of Naval Research and Fundación Biodiversidad (EU project LIFE INDEMARES) with permit from the Canary Islands and Spanish governments.
Wed, 01 Mar 2017 00:00:00 GMThttp://hdl.handle.net/10023/117122017-03-01T00:00:00ZWarren, Victoria E.Marques, Tiago A.Harris, DanielleThomas, LenTyack, Peter L.Aguilar de Soto, NatachaHickmott, Leigh S.Johnson, Mark P.Passive acoustic monitoring has become an increasingly prevalent tool for estimating density of marine mammals, such as beaked whales, which vocalize often but are difficult to survey visually. Counts of acoustic cues (e.g., vocalizations), when corrected for detection probability, can be translated into animal density estimates by applying an individual cue production rate multiplier. It is essential to understand variation in these rates to avoid biased estimates. The most direct way to measure cue production rate is with animal-mounted acoustic recorders. This study utilized data from sound recording tags deployed on Blainville's (Mesoplodon densirostris, 19 deployments) and Cuvier's (Ziphius cavirostris, 16 deployments) beaked whales, in two locations per species, to explore spatial and temporal variation in click production rates. No spatial or temporal variation was detected within the average click production rate of Blainville's beaked whales when calculated over dive cycles (including silent periods between dives); however, spatial variation was detected when averaged only over vocal periods. Cuvier's beaked whales exhibited significant spatial and temporal variation in click production rates within vocal periods and when silent periods were included. This evidence of variation emphasizes the need to utilize appropriate cue production rates when estimating density from passive acoustic data.Fine-scale harbour seal usage for informed marine spatial planninghttp://hdl.handle.net/10023/11695
High-resolution species distribution maps are required for marine spatial planning, consenting, and licensing to assess interactions between anthropogenic activities and ecosystems. This approach can inform conservation measures for protected species and facilitate commercial developments needed for economic growth. A case study centred on Orkney, UK, is an area where concern for a declining harbour seal population has led to constraints being placed on tidal energy generation developments. Telemetry data from 54 animals tagged between 2003 and 2015 were combined with terrestrial counts from 2008 to 2015 to produce density estimation maps. Predictive habitat models using GAM-GEEs provided robust predictions in areas where telemetry data were absent, and were combined with density estimation maps. Harbour seal usage maps with confidence intervals were produced around Orkney and the North coast of Scotland. The selected habitat model showed that distance from haul out, proportion of sand in seabed sediment, and peak flow of tidal current were important predictors of space-use. Fine-scale usage maps can be used in consenting and licensing of anthropogenic developments to determine local abundance. When quantifying anthropogenic impacts through changes to species distributions, usage maps could be spatially explicitly linked to individual-based models to inform predicted movement and behaviour.
The work was funded through Scottish Government MSQ0174 contract CR/2014/11; CREEM, University of St Andrews; the National Capability fund from the Natural Environment Research Council to the Sea Mammal Research Unit (grant no. SMRU1001); and MASTS pooling initiative, which is funded by the Scottish Funding Council (grant reference HR09011).
Thu, 14 Sep 2017 00:00:00 GMThttp://hdl.handle.net/10023/116952017-09-14T00:00:00ZJones, Esther LaneSparling, Carol ElizabethMcConnell, Bernie JMorris, ChristopherSmout, Sophie CarolineHigh-resolution species distribution maps are required for marine spatial planning, consenting, and licensing to assess interactions between anthropogenic activities and ecosystems. This approach can inform conservation measures for protected species and facilitate commercial developments needed for economic growth. A case study centred on Orkney, UK, is an area where concern for a declining harbour seal population has led to constraints being placed on tidal energy generation developments. Telemetry data from 54 animals tagged between 2003 and 2015 were combined with terrestrial counts from 2008 to 2015 to produce density estimation maps. Predictive habitat models using GAM-GEEs provided robust predictions in areas where telemetry data were absent, and were combined with density estimation maps. Harbour seal usage maps with confidence intervals were produced around Orkney and the North coast of Scotland. The selected habitat model showed that distance from haul out, proportion of sand in seabed sediment, and peak flow of tidal current were important predictors of space-use. Fine-scale usage maps can be used in consenting and licensing of anthropogenic developments to determine local abundance. When quantifying anthropogenic impacts through changes to species distributions, usage maps could be spatially explicitly linked to individual-based models to inform predicted movement and behaviour.Ocean observations using tagged animalshttp://hdl.handle.net/10023/11690
“Biologging” through temporary attachment of miniaturized data loggers on marine animals is revolutionizing the science of marine ecology (Block et al., 2011; Hussey et al., 2015). It also offers new capabilities to observe the ocean. In addition to collecting location and depth information useful for studying foraging behavior, these devices can record vertical profiles of temperature and salinity (Fedak, 2004; Costa et al., 2010), data that are used to improve knowledge of ocean state and its variability.
Thu, 01 Jun 2017 00:00:00 GMThttp://hdl.handle.net/10023/116902017-06-01T00:00:00ZRoquet, FabienBoehme, LarsBlock, BarbaraCharrasin, Jean BenoitCosta, DanielGuinet, ChristopheHarcourt, Robert G.Hindell, Mark A.Hückstädt, Luis A.McMahon, Clive R.Woodward, BillFedak, Michael Andre“Biologging” through temporary attachment of miniaturized data loggers on marine animals is revolutionizing the science of marine ecology (Block et al., 2011; Hussey et al., 2015). It also offers new capabilities to observe the ocean. In addition to collecting location and depth information useful for studying foraging behavior, these devices can record vertical profiles of temperature and salinity (Fedak, 2004; Costa et al., 2010), data that are used to improve knowledge of ocean state and its variability.Insights into Blainville's beaked whale (Mesoplodon densirostris) echolocation ontogeny from recordings of mother-calf pairshttp://hdl.handle.net/10023/11678
The data we report were collected during two studies, “Behavioral Response Study-2008” and “Using Satellite Telemetry to Monitor Beaked whale Movements on a Navy Range,” both funded by the U.S. Office of Naval Research (ONR). CD received funds for analysis from ONR as part of the “Population Consequences of Acoustic Disturbance” project. LR and PT were supported by the Marine Alliance for Science and Technology for Scotland (MASTS) pooling initiative and their support is gratefully acknowledged. MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions.
Sun, 01 Jan 2017 00:00:00 GMThttp://hdl.handle.net/10023/116782017-01-01T00:00:00ZDunn, CharlotteClaridge, DianeDurban, JohnShaffer, JessicaMoretti, DavidTyack, PeterRendell, LukeHarbour seals avoid tidal turbine noise : implications for collision riskhttp://hdl.handle.net/10023/11674
1. Tidal stream energy converters (turbines) are currently being installed in tidally energetic coastal sites. However, there is currently a high level of uncertainty surrounding the potential environmental impacts on marine mammals. This is a key consenting risk to commercial introduction of tidal energy technology. Concerns derive primarily from the potential for injury to marine mammals through collisions with moving components of turbines. To understand the nature of this risk, information on how animals respond to tidal turbines is urgently required. 2. We measured the behaviour of harbour seals in response to acoustic playbacks of simulated tidal turbine sound within a narrow coastal channel subject to strong, tidally induced currents. This was carried out using data from animal-borne GPS tags and shore-based observations, which were analysed to quantify behavioural responses to the turbine sound. 3. Results showed that the playback state (silent control or turbine signal) was not a significant predictor of the overall number of seals sighted within the channel. 4. However, there was a localised impact of the turbine signal; tagged harbour seals exhibited significant spatial avoidance of the sound which resulted in a reduction in the usage by seals of between 11 and 41% at the playback location. The significant decline in usage extended to 500 m from the playback location at which usage decreased by between 1 and 9% during playback. 5. Synthesis and applications: This study provides important information for policy makers looking to assess the potential impacts of tidal turbines and advise on development of the tidal energy industry. Results showing that seals avoid tidal turbine sound suggest that a proportion of seals encountering tidal turbines will exhibit behavioural responses resulting in avoidance of physical injury; in practice, the empirical changes in usage can be used directly as avoidance rates when using collision risk models to predict the effects of tidal turbines on seals. There is now a clear need to measure how marine mammals behave in response to actual operating tidal turbines in the long term to learn whether marine mammals and tidal turbines can co-exist safely at the scales currently envisaged for the industry.
The work was funded by the UK’s Natural Environment Research Council (NERC) and Department of the Environment Food and Rural Affairs (RESPONSE project, NE/J004251/1). It was also supported by NERC National Capability funding to the Sea Mammal Research Unit (grant no. SMRU1001). Data available from the Dryad Digital Repository. DOI: http://dx.doi.org/10.5061/dryad.vt2b3
Thu, 01 Mar 2018 00:00:00 GMThttp://hdl.handle.net/10023/116742018-03-01T00:00:00ZHastie, Gordon D.Russell, Debbie J. F.Lepper, PaulElliott, JimWilson, BenBenjamins, StevenThompson, Dave1. Tidal stream energy converters (turbines) are currently being installed in tidally energetic coastal sites. However, there is currently a high level of uncertainty surrounding the potential environmental impacts on marine mammals. This is a key consenting risk to commercial introduction of tidal energy technology. Concerns derive primarily from the potential for injury to marine mammals through collisions with moving components of turbines. To understand the nature of this risk, information on how animals respond to tidal turbines is urgently required. 2. We measured the behaviour of harbour seals in response to acoustic playbacks of simulated tidal turbine sound within a narrow coastal channel subject to strong, tidally induced currents. This was carried out using data from animal-borne GPS tags and shore-based observations, which were analysed to quantify behavioural responses to the turbine sound. 3. Results showed that the playback state (silent control or turbine signal) was not a significant predictor of the overall number of seals sighted within the channel. 4. However, there was a localised impact of the turbine signal; tagged harbour seals exhibited significant spatial avoidance of the sound which resulted in a reduction in the usage by seals of between 11 and 41% at the playback location. The significant decline in usage extended to 500 m from the playback location at which usage decreased by between 1 and 9% during playback. 5. Synthesis and applications: This study provides important information for policy makers looking to assess the potential impacts of tidal turbines and advise on development of the tidal energy industry. Results showing that seals avoid tidal turbine sound suggest that a proportion of seals encountering tidal turbines will exhibit behavioural responses resulting in avoidance of physical injury; in practice, the empirical changes in usage can be used directly as avoidance rates when using collision risk models to predict the effects of tidal turbines on seals. There is now a clear need to measure how marine mammals behave in response to actual operating tidal turbines in the long term to learn whether marine mammals and tidal turbines can co-exist safely at the scales currently envisaged for the industry.Marine mammals exploring the oceans pole to pole : a review of the MEOP consortiumhttp://hdl.handle.net/10023/11647
Polar oceans are poorly monitored despite the important role they play in regulating the Earth’s climate system. Marine mammals equipped with biologging devices are now being used to fill the data gaps in these logistically difficult to sample regions. Since 2002, instrumented animals have been generating exceptionally large datasets of oceanographic CTD casts (> 500 000 profiles), which are now freely available to the scientific community through the MEOP data portal (http://meop.net). MEOP (Marine Mammals Exploring the Oceans Pole to Pole) is a consortium of international researchers dedicated to sharing animal-derived data and knowledge about the polar oceans. Collectively, MEOP demonstrates the power and cost-effectiveness of using marine mammals as data-collection platforms that can dramatically improve the ocean-observing system for biological and physical oceanographers. Here, we review the MEOP program and database to bring it to the attention of the international community.
Thu, 01 Jun 2017 00:00:00 GMThttp://hdl.handle.net/10023/116472017-06-01T00:00:00ZTreasure, AnneRoquet, FabienAnsorge, Isabelle J.Bester, Marthán N.Boehme, LarsBornemann, HorstCharrassin, Jean-BenoitChevallier, DamienCosta, Daniel P.Fedak, Michael AndreGuinet, ChristopheHammill, Mike O.Harcourt, Robert G.Hindell, Mark A.Kovacs, Kit M.Lea, Mary-AnneLovell, PhilipLowther, Andrew D.Lydersen, ChristianMcIntyre, TrevorMcMahon, Clive R.Muelbert, Mônica M.C.Nicholls, KeithPicard, BaptisteReverdin, GillesTrites, Andrew W.Williams, Guy D.de Bruyn, P.J. NicoPolar oceans are poorly monitored despite the important role they play in regulating the Earth’s climate system. Marine mammals equipped with biologging devices are now being used to fill the data gaps in these logistically difficult to sample regions. Since 2002, instrumented animals have been generating exceptionally large datasets of oceanographic CTD casts (> 500 000 profiles), which are now freely available to the scientific community through the MEOP data portal (http://meop.net). MEOP (Marine Mammals Exploring the Oceans Pole to Pole) is a consortium of international researchers dedicated to sharing animal-derived data and knowledge about the polar oceans. Collectively, MEOP demonstrates the power and cost-effectiveness of using marine mammals as data-collection platforms that can dramatically improve the ocean-observing system for biological and physical oceanographers. Here, we review the MEOP program and database to bring it to the attention of the international community.Multi-decadal and ontogenetic trophic shifts inferred from stable isotope ratios of pinniped teethhttp://hdl.handle.net/10023/11554
Identifying and characterizing top predators’ use of trophic resources provides important information about animal ecology and their response to changing conditions. Information from sources such as stable isotopes can be used to infer changes in resource use as direct observations in the wildare difficult to obtain, particularly in the marine environment. Stable carbon and nitrogen isotope values were recovered from the canine teeth of grey seals collected from haul outs in the central North Sea in the 1970/80s (n = 44) and 2000s (n = 25), spanning a period of marked ecosystem changes in the region. Extracting material deposited during juvenile and adult life-stages, we reconstructed a multi-decadal record ofδ15N and δ13C variation. Using established correlations between stable isotope ratios and sea bottom temperature we created a proxy for baseline isotopic variability to account for this source of temporal change. We found(1) a significant long-term decline in juvenile grey seal δ15N values,suggesting trophic position has decreased over time; (2) a decline in adultδ15N values and contraction in stable isotopic niche space after the North Sea regime shift, signifying both a decline in trophic position and change in foraging habits over the 20th century; and (3) evidence for dietary segregation between juvenile and adult animals, showing juvenile individuals feeding at a lower trophic position and in more nearshore areas than adults. Our results demonstrate the efficacy of mining archived biological samples to address ecological questions and imply important ontogenetic and long-term shifts in the feeding ecology of a top predator.Long-term changes in grey seal trophic dynamics may be partly in response to well documented ecosystem changes in the North Sea. Such indirect monitoring of marine predators may have utility when set in the context of ecosystem assessments where paucity of long-term monitoring data is prevalent.
This work was supported by National Capability funding from the Natural Environment Research Council to the Sea Mammal Research Unit (grant no. SMRU1001).
Mon, 01 Jan 2018 00:00:00 GMThttp://hdl.handle.net/10023/115542018-01-01T00:00:00ZHanson, Nora N.Jones, Esther LaneHarris, RobertIdentifying and characterizing top predators’ use of trophic resources provides important information about animal ecology and their response to changing conditions. Information from sources such as stable isotopes can be used to infer changes in resource use as direct observations in the wildare difficult to obtain, particularly in the marine environment. Stable carbon and nitrogen isotope values were recovered from the canine teeth of grey seals collected from haul outs in the central North Sea in the 1970/80s (n = 44) and 2000s (n = 25), spanning a period of marked ecosystem changes in the region. Extracting material deposited during juvenile and adult life-stages, we reconstructed a multi-decadal record ofδ15N and δ13C variation. Using established correlations between stable isotope ratios and sea bottom temperature we created a proxy for baseline isotopic variability to account for this source of temporal change. We found(1) a significant long-term decline in juvenile grey seal δ15N values,suggesting trophic position has decreased over time; (2) a decline in adultδ15N values and contraction in stable isotopic niche space after the North Sea regime shift, signifying both a decline in trophic position and change in foraging habits over the 20th century; and (3) evidence for dietary segregation between juvenile and adult animals, showing juvenile individuals feeding at a lower trophic position and in more nearshore areas than adults. Our results demonstrate the efficacy of mining archived biological samples to address ecological questions and imply important ontogenetic and long-term shifts in the feeding ecology of a top predator.Long-term changes in grey seal trophic dynamics may be partly in response to well documented ecosystem changes in the North Sea. Such indirect monitoring of marine predators may have utility when set in the context of ecosystem assessments where paucity of long-term monitoring data is prevalent.Passive acoustic methods for fine-scale tracking of harbour porpoises in tidal rapidshttp://hdl.handle.net/10023/11549
The growing interest in generating electrical power from tidal currents using tidal turbine generators raises a number of environmental concerns, including the risk that marine mammals might be injured or killed through collision with rotating turbine blades. To understand this risk, information on how marine mammals use tidal rapid habitats and in particular, their underwater movements and dive behaviour is required. Porpoises, which are the most abundant small cetacean at most European tidal sites, are difficult animals to tag, and the limited size of tidal habitats means that any telemetered animal would be likely to spend only a small proportion of time within them. Here, an alternative approach is explored, whereby passive acoustic monitoring (PAM) is used to obtain fine scale geo-referenced tracks of harbour porpoises in tidal rapid areas. Large aperture hydrophone arrays are required to obtain accurate locations of animals from PAM data and automated algorithms are necessary to process the large quantities of acoustic data collected on such systems during a typical survey. Methods to automate localisation, including a method to match porpoise detections on different hydrophones and separate different vocalising animals, and an assessment of the localisation accuracy of the large aperture hydrophone array are presented.
Wed, 01 Feb 2017 00:00:00 GMThttp://hdl.handle.net/10023/115492017-02-01T00:00:00ZMacAulay, Jamie Donald JohnGordon, Jonathan Charles DavidGillespie, Douglas MichaelMalinka, Chloe ElizabethNorthridge, Simon PatrickThe growing interest in generating electrical power from tidal currents using tidal turbine generators raises a number of environmental concerns, including the risk that marine mammals might be injured or killed through collision with rotating turbine blades. To understand this risk, information on how marine mammals use tidal rapid habitats and in particular, their underwater movements and dive behaviour is required. Porpoises, which are the most abundant small cetacean at most European tidal sites, are difficult animals to tag, and the limited size of tidal habitats means that any telemetered animal would be likely to spend only a small proportion of time within them. Here, an alternative approach is explored, whereby passive acoustic monitoring (PAM) is used to obtain fine scale geo-referenced tracks of harbour porpoises in tidal rapid areas. Large aperture hydrophone arrays are required to obtain accurate locations of animals from PAM data and automated algorithms are necessary to process the large quantities of acoustic data collected on such systems during a typical survey. Methods to automate localisation, including a method to match porpoise detections on different hydrophones and separate different vocalising animals, and an assessment of the localisation accuracy of the large aperture hydrophone array are presented.Pollinator importance networks illustrate the crucial value of bees in a highly speciose plant communityhttp://hdl.handle.net/10023/11526
Accurate predictions of pollination service delivery require a comprehensive understanding of the interactions between plants and flower visitors. To improve measurements of pollinator performance underlying such predictions, we surveyed visitation frequency, pollinator effectiveness (pollen deposition ability) and pollinator importance (the product of visitation frequency and effectiveness) of flower visitors in a diverse Mediterranean flower meadow. With these data we constructed the largest pollinator importance network to date and compared it with the corresponding visitation network to estimate the specialisation of the community with greater precision. Visitation frequencies at the community level were positively correlated with the amount of pollen deposited during individual visits, though rarely correlated at lower taxonomic resolution. Bees had the highest levels of pollinator effectiveness, with Apis, Andrena, Lasioglossum and Osmiini bees being the most effective visitors to a number of plant species. Bomblyiid flies were the most effective non-bee flower visitors. Predictions of community specialisation (H2′) were higher in the pollinator importance network than the visitation network, mirroring previous studies. Our results increase confidence in existing measures of pollinator redundancy at the community level using visitation data, while also providing detailed information on interaction quality at the plant species level.
This research was funded by the Natural Environmental Research Council (grant no. NE/K004522/1).
Mon, 21 Aug 2017 00:00:00 GMThttp://hdl.handle.net/10023/115262017-08-21T00:00:00ZBallantyne, GavinBaldock, Katherine C. R.Rendell, LukeWillmer, P. G.Accurate predictions of pollination service delivery require a comprehensive understanding of the interactions between plants and flower visitors. To improve measurements of pollinator performance underlying such predictions, we surveyed visitation frequency, pollinator effectiveness (pollen deposition ability) and pollinator importance (the product of visitation frequency and effectiveness) of flower visitors in a diverse Mediterranean flower meadow. With these data we constructed the largest pollinator importance network to date and compared it with the corresponding visitation network to estimate the specialisation of the community with greater precision. Visitation frequencies at the community level were positively correlated with the amount of pollen deposited during individual visits, though rarely correlated at lower taxonomic resolution. Bees had the highest levels of pollinator effectiveness, with Apis, Andrena, Lasioglossum and Osmiini bees being the most effective visitors to a number of plant species. Bomblyiid flies were the most effective non-bee flower visitors. Predictions of community specialisation (H2′) were higher in the pollinator importance network than the visitation network, mirroring previous studies. Our results increase confidence in existing measures of pollinator redundancy at the community level using visitation data, while also providing detailed information on interaction quality at the plant species level.Harbour seals (Phoca vitulina) around an operational tidal turbine in Strangford Narrows : no barrier effect but small changes in transit behaviourhttp://hdl.handle.net/10023/11512
1. Data were obtained from 32 electronic tags that were glued to the fur of harbour seals (Phoca vitulina) in and around Strangford Lough, Northern Ireland, during the environmental monitoring of the SeaGen tidal turbine. 2. This study provides the first detailed information on the behaviour of marine mammals close to a commercial-scale tidal energy device. The turbine did not prevent transit of the animals through the channel and therefore did not result in a ‘barrier’ effect. 3. However, the animals' behaviour did change when the turbine was operating, demonstrating the importance of allowing for behavioural responses when estimating collision risks associated with tidal turbines. 4. Tagged animals passed the location of the device more frequently during slack water than when the current was running. In 2010 the frequency of transits by tagged seals reduced by 20% (95% CI: 10–50%) when the turbine was on, relative to when it was off. This effect was stronger when considering daylight hours only with a reduction of transit rate of 57% (95% CI: 25–64%). Seals tagged during the operational period transited approximately 250 m either side of the turbine suggesting some degree of local avoidance compared with the pre-installation results. 5. The results presented here have implications for monitoring and managing the potential interactions between tidal turbines and marine wildlife. Principally that the design of telemetry studies for measuring change in response to developments should seek to understand and take into account variability in seal behaviour. 6. This study only looked at the effects of a single turbine rather than an array, and mitigation limited the ability to determine close range interactions. However, the study indicates that the effect of the turbine on Strangford Lough harbour seals was minor and that collision risk was reduced by the behaviour of the seals.
Funding: NERC Marine Renewable Energy Knowledge Exchange Programme (Contract 4060038637) and NERC grant SMRU1001.
Thu, 01 Feb 2018 00:00:00 GMThttp://hdl.handle.net/10023/115122018-02-01T00:00:00ZSparling, Carol ElizabethLonergan, MikeMcConnell, Bernie J1. Data were obtained from 32 electronic tags that were glued to the fur of harbour seals (Phoca vitulina) in and around Strangford Lough, Northern Ireland, during the environmental monitoring of the SeaGen tidal turbine. 2. This study provides the first detailed information on the behaviour of marine mammals close to a commercial-scale tidal energy device. The turbine did not prevent transit of the animals through the channel and therefore did not result in a ‘barrier’ effect. 3. However, the animals' behaviour did change when the turbine was operating, demonstrating the importance of allowing for behavioural responses when estimating collision risks associated with tidal turbines. 4. Tagged animals passed the location of the device more frequently during slack water than when the current was running. In 2010 the frequency of transits by tagged seals reduced by 20% (95% CI: 10–50%) when the turbine was on, relative to when it was off. This effect was stronger when considering daylight hours only with a reduction of transit rate of 57% (95% CI: 25–64%). Seals tagged during the operational period transited approximately 250 m either side of the turbine suggesting some degree of local avoidance compared with the pre-installation results. 5. The results presented here have implications for monitoring and managing the potential interactions between tidal turbines and marine wildlife. Principally that the design of telemetry studies for measuring change in response to developments should seek to understand and take into account variability in seal behaviour. 6. This study only looked at the effects of a single turbine rather than an array, and mitigation limited the ability to determine close range interactions. However, the study indicates that the effect of the turbine on Strangford Lough harbour seals was minor and that collision risk was reduced by the behaviour of the seals.Short first click intervals in echolocation trains of three species of deep diving odontoceteshttp://hdl.handle.net/10023/11502
All odontocetes produce echolocation clicks as part of their vocal repertoire. In this paper we analysed inter-click-intervals in recordings from suction cup tags with a focus on the first inter-click interval of each click train. We refer to shorter first inter-click intervals as short first intervals (SFIs). We found that the context of SFI occurrence varies across three deep-diving species. In Blainville’s beaked whales, 87% of click trains that were preceded by a terminal buzz started with SFIs. In Cuvier’s beaked whales, only sub-adult animals produced notable amounts of SFIs. In contrast, sperm whales were much more likely to produce SFIs on the first click train of a dive. While the physiological and/or behavioural reasons for SFI click production are unknown, species differences in their production could provide a window into the evolution of odontocete echolocation.
LR and PT were supported by the Marine Alliance for Science and Technology for Scotland (MASTS) pooling initiative and their support is gratefully acknowledged. MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions.
Wed, 01 Feb 2017 00:00:00 GMThttp://hdl.handle.net/10023/115022017-02-01T00:00:00ZDunn, CharlotteTyack, Peter LloydMiller, PatrickRendell, Luke EdwardAll odontocetes produce echolocation clicks as part of their vocal repertoire. In this paper we analysed inter-click-intervals in recordings from suction cup tags with a focus on the first inter-click interval of each click train. We refer to shorter first inter-click intervals as short first intervals (SFIs). We found that the context of SFI occurrence varies across three deep-diving species. In Blainville’s beaked whales, 87% of click trains that were preceded by a terminal buzz started with SFIs. In Cuvier’s beaked whales, only sub-adult animals produced notable amounts of SFIs. In contrast, sperm whales were much more likely to produce SFIs on the first click train of a dive. While the physiological and/or behavioural reasons for SFI click production are unknown, species differences in their production could provide a window into the evolution of odontocete echolocation.Using blubber explants to investigate adipose function in grey seals : glycolytic, lipolytic and gene expression responses to glucose and hydrocortisonehttp://hdl.handle.net/10023/11466
Adipose tissue is fundamental to energy balance, which underpins fitness and survival. Knowledge of adipose regulation in animals that undergo rapid fat deposition and mobilisation aids understanding of their energetic responses to rapid environmental change. Tissue explants can be used to investigate adipose regulation in wildlife species with large fat reserves, when opportunities for organismal experimental work are limited. We investigated glucose removal, lactate, glycerol and NEFA accumulation in media, and metabolic gene expression in blubber explants from wild grey seals. Glycolysis was higher in explants incubated in 25 mM glucose (HG) for 24 h compared to controls (C: 5.5 mM glucose). Adipose-derived lactate likely contributes to high endogenous glucose production in seals. Lipolysis was not stimulated by HG or high hydrocortisone (HC: 500 nM hydrocortisone) and was lower in heavier animals. HC caused NEFA accumulation in media to decrease by ~30% relative to C in females, indicative of increased lipogenesis. Lipolysis was higher in males than females in C and HG conditions. Lower relative abundance of 11-β-hydroxysteroid dehydrogenase 1 mRNA in HG explants suggests glucose involvement in blubber cortisol sensitivity. Our findings can help predict energy balance responses to stress and nutritional state in seals, and highlight the use of explants to study fat tissue function in wildlife.
This work was funded by an early career grant to KAB from the Royal Society and Natural Environment Research Council National Capability funding to AJH (grant number SMRU/1001).
Thu, 10 Aug 2017 00:00:00 GMThttp://hdl.handle.net/10023/114662017-08-10T00:00:00ZBennett, Kimberley A.Robinson, Kelly J.Moss, Simon E. W.Millward, SebastianHall, Ailsa J.Adipose tissue is fundamental to energy balance, which underpins fitness and survival. Knowledge of adipose regulation in animals that undergo rapid fat deposition and mobilisation aids understanding of their energetic responses to rapid environmental change. Tissue explants can be used to investigate adipose regulation in wildlife species with large fat reserves, when opportunities for organismal experimental work are limited. We investigated glucose removal, lactate, glycerol and NEFA accumulation in media, and metabolic gene expression in blubber explants from wild grey seals. Glycolysis was higher in explants incubated in 25 mM glucose (HG) for 24 h compared to controls (C: 5.5 mM glucose). Adipose-derived lactate likely contributes to high endogenous glucose production in seals. Lipolysis was not stimulated by HG or high hydrocortisone (HC: 500 nM hydrocortisone) and was lower in heavier animals. HC caused NEFA accumulation in media to decrease by ~30% relative to C in females, indicative of increased lipogenesis. Lipolysis was higher in males than females in C and HG conditions. Lower relative abundance of 11-β-hydroxysteroid dehydrogenase 1 mRNA in HG explants suggests glucose involvement in blubber cortisol sensitivity. Our findings can help predict energy balance responses to stress and nutritional state in seals, and highlight the use of explants to study fat tissue function in wildlife.Seals and shipping : quantifying population risk and individual exposure to vessel noisehttp://hdl.handle.net/10023/11459
1. Vessels can have acute and chronic impacts on marine species. The rate of increase in commercial shipping is accelerating, and there is a need to quantify and potentially manage the risk of these impacts. 2. Usage maps characterising densities of grey and harbour seals and ships around the British Isles were used to produce risk maps of seal co-occurrence with shipping traffic. Acoustic exposure to individual harbour seals was modelled in a study area using contemporaneous movement data from 28 animals fitted with UHF global positioning satellite telemetry tags and automatic identification system data from all ships during 2014 and 2015. Data from four acoustic recorders were used to validate sound exposure predictions. 3. Across the British Isles, rates of co-occurrence were highest within 50 km of the coast, close to seal haul-outs. Areas identified with high risk of exposure included 11 Special Areas of Conservation (SAC; from a possible 25). Risk to harbour seal populations was highest, affecting half of all SACs associated with the species. 4. Predicted cumulative sound exposure level, cSELs(Mpw), over all seals was 176·8 dB re 1 μPa2 s (95% CI 163·3–190·4), ranging from 170·2 dB re 1μPa2 s (95% CI 168·4–171·9) to 189·3 dB re 1 μPa2 s (95% CI 172·6–206·0) for individuals. This represented an increase in 28·3 dB re 1 μPa2 s over measured ambient noise. For 20 of 28 animals in the study, 95% CI for cSELs(Mpw) had upper bounds above levels known to induce temporary threshold shift. Predictions of broadband received sound pressure levels were underestimated on average by 0·7 dB re 1 μPa (±3·3). 5. Synthesis and applications. We present a framework to allow shipping noise, an important marine anthropogenic stressor, to be explicitly incorporated into spatial planning. Potentially sensitive areas are identified through quantifying risk to marine species of exposure to shipping traffic, and individual noise exposure is predicted with associated uncertainty in an area with varying rates of co-occurrence. The detailed approach taken here facilitates spatial planning with regard to underwater noise within areas protected through the Habitats Directive, and could be used to provide evidence for further designations. This framework may have utility in assessing whether underwater noise levels are at Good Environmental Status under the Marine Strategy Framework Directive.
The work was funded under Scottish Government grant MMSS/001/11 and contract CR/2014/04, and supported by National Capability funding from NERC to SMRU (grant no. SMRU1001). Seal at-sea usage maps, location data for individual seals, locations and source levels for vessels, and SPLs from monitoring data used for acoustic validations are available from the Pure repository, https://doi.org/10.17630/89ac9345-240a-41bb-8f53-b3f14bb114c0.
Fri, 01 Dec 2017 00:00:00 GMThttp://hdl.handle.net/10023/114592017-12-01T00:00:00ZJones, Esther L.Hastie, Gordon D.Smout, SophieOnoufriou, JosephMerchant, Nathan D.Brookes, Kate L.Thompson, David1. Vessels can have acute and chronic impacts on marine species. The rate of increase in commercial shipping is accelerating, and there is a need to quantify and potentially manage the risk of these impacts. 2. Usage maps characterising densities of grey and harbour seals and ships around the British Isles were used to produce risk maps of seal co-occurrence with shipping traffic. Acoustic exposure to individual harbour seals was modelled in a study area using contemporaneous movement data from 28 animals fitted with UHF global positioning satellite telemetry tags and automatic identification system data from all ships during 2014 and 2015. Data from four acoustic recorders were used to validate sound exposure predictions. 3. Across the British Isles, rates of co-occurrence were highest within 50 km of the coast, close to seal haul-outs. Areas identified with high risk of exposure included 11 Special Areas of Conservation (SAC; from a possible 25). Risk to harbour seal populations was highest, affecting half of all SACs associated with the species. 4. Predicted cumulative sound exposure level, cSELs(Mpw), over all seals was 176·8 dB re 1 μPa2 s (95% CI 163·3–190·4), ranging from 170·2 dB re 1μPa2 s (95% CI 168·4–171·9) to 189·3 dB re 1 μPa2 s (95% CI 172·6–206·0) for individuals. This represented an increase in 28·3 dB re 1 μPa2 s over measured ambient noise. For 20 of 28 animals in the study, 95% CI for cSELs(Mpw) had upper bounds above levels known to induce temporary threshold shift. Predictions of broadband received sound pressure levels were underestimated on average by 0·7 dB re 1 μPa (±3·3). 5. Synthesis and applications. We present a framework to allow shipping noise, an important marine anthropogenic stressor, to be explicitly incorporated into spatial planning. Potentially sensitive areas are identified through quantifying risk to marine species of exposure to shipping traffic, and individual noise exposure is predicted with associated uncertainty in an area with varying rates of co-occurrence. The detailed approach taken here facilitates spatial planning with regard to underwater noise within areas protected through the Habitats Directive, and could be used to provide evidence for further designations. This framework may have utility in assessing whether underwater noise levels are at Good Environmental Status under the Marine Strategy Framework Directive.Development of an animal-borne blood sample collection device and its deployment for the determination of cardiovascular and stress hormones in phocid sealshttp://hdl.handle.net/10023/11456
An animal-borne blood sampler with data-logging functions was developed for phocid seals, which collected two blood samples for the comparison of endocrino-logical/biochemical parameters under two different conditions. The sampler can be triggered by preset hydrostatic pressure, acceleration (descending or ascending), temperature, and time, and also man-ually by light. The sampling was reliable with 39/50 (78%) successful attempts to collect blood samples. Contamination of fluids in the tubing to the next blood sample was 1%, following the prior clearance of the tubing to a waste syringe. In captive harbor seals (Phoca vitulina), the automated blood-sampling method was less stressful than direct blood withdrawal, as evidenced by lower levels of stress hormones (P < 0.05 for ACTH and P = 0.078 for cortisol). HPLC analyses showed that both cortisol and cortisone were circu-lating in seal blood. Using the sampler, plasma levels of cardiovascular hormones, atrial natriuretic peptide (ANP), AVP, and ANG II were compared in grey seals (Halichoerus grypus), between samples collected when the animals were on land and in the water. HPLC analyses determined that [Met12] ANP (1-28) and various forms of angiotensins (ANG II, III, and IV) were circulating in seal blood. Although water immersion profoundly changes the plasma levels of cardiovascular hormones in terrestrial mammals, there were only tendencies toward an increase in ANP (P = 0.069) and a decrease in AVP (P = 0.074) in the seals. These results suggest that cardiovascular regulation in phocid seals may have undergone adaptation during evolution of the carnivore to a semiaquatic lifestyle.
The research was supported by Bilateral Program between Japan and the United Kingdom and a Grant-in-Aid for Scientific Research (23247010) to Y. Takei and by Grant-in-Aid for challenging Exploratory Research (15K14567) to I. Suzuki from the Japan Society for the Promotion of Science. This work was also supported by funding from the U.K. Natural Environment Research Council (Grant SMRU1001).
Sat, 01 Oct 2016 00:00:00 GMThttp://hdl.handle.net/10023/114562016-10-01T00:00:00ZTakei, YoshioSuzuki, IppeiWong, Marty K. S.Milne, RyanMoss, SimonSato, KatsufumiHall, AilsaAn animal-borne blood sampler with data-logging functions was developed for phocid seals, which collected two blood samples for the comparison of endocrino-logical/biochemical parameters under two different conditions. The sampler can be triggered by preset hydrostatic pressure, acceleration (descending or ascending), temperature, and time, and also man-ually by light. The sampling was reliable with 39/50 (78%) successful attempts to collect blood samples. Contamination of fluids in the tubing to the next blood sample was 1%, following the prior clearance of the tubing to a waste syringe. In captive harbor seals (Phoca vitulina), the automated blood-sampling method was less stressful than direct blood withdrawal, as evidenced by lower levels of stress hormones (P < 0.05 for ACTH and P = 0.078 for cortisol). HPLC analyses showed that both cortisol and cortisone were circu-lating in seal blood. Using the sampler, plasma levels of cardiovascular hormones, atrial natriuretic peptide (ANP), AVP, and ANG II were compared in grey seals (Halichoerus grypus), between samples collected when the animals were on land and in the water. HPLC analyses determined that [Met12] ANP (1-28) and various forms of angiotensins (ANG II, III, and IV) were circulating in seal blood. Although water immersion profoundly changes the plasma levels of cardiovascular hormones in terrestrial mammals, there were only tendencies toward an increase in ANP (P = 0.069) and a decrease in AVP (P = 0.074) in the seals. These results suggest that cardiovascular regulation in phocid seals may have undergone adaptation during evolution of the carnivore to a semiaquatic lifestyle.Animal Counting Toolkit : a practical guide to small-boat surveys for estimating abundance of coastal marine mammalshttp://hdl.handle.net/10023/11430
Small cetaceans (dolphins and porpoises) face serious anthropogenic threats in coastal habitats. These include bycatch in fisheries; exposure to noise, plastic and chemical pollution; disturbance from boaters; and climate change. Generating reliable abundance estimates is essential to assess sustainability of bycatch in fishing gear or any other form of anthropogenic removals and to design conservation and recovery plans for endangered species. Cetacean abundance estimates are lacking from many coastal waters of many developing countries. Lack of funding and training opportunities makes it difficult to fill in data gaps. Even if international funding were found for surveys in developing countries, building local capacity would be necessary to sustain efforts over time to detect trends and monitor biodiversity loss. Large-scale, shipboard surveys can cost tens of thousands of US dollars each day. We focus on methods to generate preliminary abundance estimates from low-cost, small-boat surveys that embrace a ‘training-while-doing’ approach to fill in data gaps while simultaneously building regional capacity for data collection. Our toolkit offers practical guidance on simple design and field data collection protocols that work with small boats and small budgets, but expect analysis to involve collaboration with a quantitative ecologist or statistician. Our audience includes independent scientists, government conservation agencies, NGOs and indigenous coastal communities, with a primary focus on fisheries bycatch. We apply our Animal Counting Toolkit to a small-boat survey in Canada’s Pacific coastal waters to illustrate the key steps in collecting line transect survey data used to estimate and monitor marine mammal abundance.
The authors thank Synchronicity Earth, Marisla Foundation, and the US Marine Mammal Commission for seed funding for this program.
Thu, 10 Aug 2017 00:00:00 GMThttp://hdl.handle.net/10023/114302017-08-10T00:00:00ZWilliams, RobAshe, Erin ElizabethGaut, KatieGryba, RowennaMoore, Jeffrey E.Rexstad, EricSandilands, DougSteventon, JustinReeves, RandallSmall cetaceans (dolphins and porpoises) face serious anthropogenic threats in coastal habitats. These include bycatch in fisheries; exposure to noise, plastic and chemical pollution; disturbance from boaters; and climate change. Generating reliable abundance estimates is essential to assess sustainability of bycatch in fishing gear or any other form of anthropogenic removals and to design conservation and recovery plans for endangered species. Cetacean abundance estimates are lacking from many coastal waters of many developing countries. Lack of funding and training opportunities makes it difficult to fill in data gaps. Even if international funding were found for surveys in developing countries, building local capacity would be necessary to sustain efforts over time to detect trends and monitor biodiversity loss. Large-scale, shipboard surveys can cost tens of thousands of US dollars each day. We focus on methods to generate preliminary abundance estimates from low-cost, small-boat surveys that embrace a ‘training-while-doing’ approach to fill in data gaps while simultaneously building regional capacity for data collection. Our toolkit offers practical guidance on simple design and field data collection protocols that work with small boats and small budgets, but expect analysis to involve collaboration with a quantitative ecologist or statistician. Our audience includes independent scientists, government conservation agencies, NGOs and indigenous coastal communities, with a primary focus on fisheries bycatch. We apply our Animal Counting Toolkit to a small-boat survey in Canada’s Pacific coastal waters to illustrate the key steps in collecting line transect survey data used to estimate and monitor marine mammal abundance.What's in a voice? Dolphins do not use voice cues for individual recognitionhttp://hdl.handle.net/10023/11422
Most mammals can accomplish acoustic recognition of other individuals by means of “voice cues,” whereby characteristics of the vocal tract render vocalizations of an individual uniquely identifiable. However, sound production in dolphins takes place in gas-filled nasal sacs that are affected by pressure changes, potentially resulting in a lack of reliable voice cues. It is well known that bottlenose dolphins learn to produce individually distinctive signature whistles for individual recognition, but it is not known whether they may also use voice cues. To investigate this question, we played back non-signature whistles to wild dolphins during brief capture-release events in Sarasota Bay, Florida. We hypothesized that non-signature whistles, which have varied contours that can be shared among individuals, would be recognizable to dolphins only if they contained voice cues. Following established methodology used in two previous sets of playback experiments, we found that dolphins did not respond differentially to non-signature whistles of close relatives versus known unrelated individuals. In contrast, our previous studies showed that in an identical context, dolphins reacted strongly to hearing the signature whistle or even a synthetic version of the signature whistle of a close relative. Thus, we conclude that dolphins likely do not use voice cues to identify individuals. The low reliability of voice cues and the need for individual recognition were likely strong selective forces in the evolution of vocal learning in dolphins.
Fieldwork for this study was funded by Harbor Branch Oceanographic Institution, Grossman Family Foundation, Dolphin Quest, Inc., NOAA Fisheries, Disney, the Office of Naval Research, Morris Animal Foundations Betty White Wildlife Rapid Response Fund, the Batchelor Foundation, and the Joint Industry Program.
Wed, 01 Nov 2017 00:00:00 GMThttp://hdl.handle.net/10023/114222017-11-01T00:00:00ZSayigh, LaelaWells, RandallJanik, Vincent M.Most mammals can accomplish acoustic recognition of other individuals by means of “voice cues,” whereby characteristics of the vocal tract render vocalizations of an individual uniquely identifiable. However, sound production in dolphins takes place in gas-filled nasal sacs that are affected by pressure changes, potentially resulting in a lack of reliable voice cues. It is well known that bottlenose dolphins learn to produce individually distinctive signature whistles for individual recognition, but it is not known whether they may also use voice cues. To investigate this question, we played back non-signature whistles to wild dolphins during brief capture-release events in Sarasota Bay, Florida. We hypothesized that non-signature whistles, which have varied contours that can be shared among individuals, would be recognizable to dolphins only if they contained voice cues. Following established methodology used in two previous sets of playback experiments, we found that dolphins did not respond differentially to non-signature whistles of close relatives versus known unrelated individuals. In contrast, our previous studies showed that in an identical context, dolphins reacted strongly to hearing the signature whistle or even a synthetic version of the signature whistle of a close relative. Thus, we conclude that dolphins likely do not use voice cues to identify individuals. The low reliability of voice cues and the need for individual recognition were likely strong selective forces in the evolution of vocal learning in dolphins.Effects of age and reproductive status on individual foraging site fidelity in a long-lived marine predatorhttp://hdl.handle.net/10023/11413
Individual foraging specializations, where individuals use a small component of the population niche width, are widespread in nature with important ecological and evolutionary implications. In long-lived animals, foraging ability develops with age, but we know little about the ontogeny of individuality in foraging. Here we use precision global positioning system (GPS) loggers to examine how individual foraging site fidelity (IFSF), a common component of foraging specialization, varies between breeders, failed breeders and immatures in a long-lived marine predator— the northern gannet Morus bassanus. Breeders (aged 5+) showed strong IFSF: they had similar routes and were faithful to distal points during successive trips. However, centrally placed immatures (aged 2–3) were far more exploratory and lacked route or foraging site fidelity. Failed breeders were intermediate: some with strong fidelity, others being more exploratory. Individual foraging specializations were previously thought to arise as a function of heritable phenotypic differences or via social transmission. Our results instead suggest a third alternative—in long-lived species foraging sites are learned during exploratory behaviours early in life, which become canalized with age and experience, and refined where possible— the exploration-refinement foraging hypothesis. We speculate similar patterns may be present in other long-lived species and moreover that long periods of immaturity may be a consequence of such memory-based individual foraging strategies.
This work was funded by the Natural Environment Research Council (Standard grant no. NE/H007466/1; New Investigators grant no. NE/H007466/1) and a German Academic Exchange Service (DAAD) Postdoctoral Fellowship and a Leadership Fellowship by the University of Glasgow to J.W.E.J. Data are available via Dryad (http://dx.doi.org/10.5061/dryad.8m1nf)
Wed, 26 Jul 2017 00:00:00 GMThttp://hdl.handle.net/10023/114132017-07-26T00:00:00ZVotier, Stephen C.Fayet, Annette L.Bearhop, StuartBodey, Thomas W.Clark, Bethany L.Grecian, JamesGuilford, TimHamer, Keith C.Jeglinski, Jana W. E.Morgan, GregWakefield, EwanPatrick, Samantha C.Individual foraging specializations, where individuals use a small component of the population niche width, are widespread in nature with important ecological and evolutionary implications. In long-lived animals, foraging ability develops with age, but we know little about the ontogeny of individuality in foraging. Here we use precision global positioning system (GPS) loggers to examine how individual foraging site fidelity (IFSF), a common component of foraging specialization, varies between breeders, failed breeders and immatures in a long-lived marine predator— the northern gannet Morus bassanus. Breeders (aged 5+) showed strong IFSF: they had similar routes and were faithful to distal points during successive trips. However, centrally placed immatures (aged 2–3) were far more exploratory and lacked route or foraging site fidelity. Failed breeders were intermediate: some with strong fidelity, others being more exploratory. Individual foraging specializations were previously thought to arise as a function of heritable phenotypic differences or via social transmission. Our results instead suggest a third alternative—in long-lived species foraging sites are learned during exploratory behaviours early in life, which become canalized with age and experience, and refined where possible— the exploration-refinement foraging hypothesis. We speculate similar patterns may be present in other long-lived species and moreover that long periods of immaturity may be a consequence of such memory-based individual foraging strategies.Marine mammals and sonar : dose-response studies, the risk-disturbance hypothesis and the role of exposure contexthttp://hdl.handle.net/10023/11259
1. Marine mammals may be negatively affected by anthropogenic noise. Behavioural response studies (BRSs) aim to establish a relationship between the exposure dose of a stressor and associated behavioural responses of animals. A recent series of BRSs have focused on the effects of naval sonar on cetaceans. Here we review the current state of understanding of the impact of sonar on marine mammals and highlight knowledge gaps and future research priorities. 2. Many marine mammal species exhibit responses to naval sonar. However, responses are highly variable between and within individuals, species and populations, highlighting the importance of context in modulating dose-response relationships. 3. There is increasing support for the risk-disturbance hypothesis as an underlying response mechanism. This hypothesis proposes that sonar sounds may be perceived by animals as a threat, evoking an evolved anti-predator response. An understanding of responses within both the dose-response and risk-disturbance frameworks may enhance our ability to predict responsiveness for unstudied species and populations. 4. Many observed behavioural responses are energetically costly, but the way in which these responses may lead to long-term individual and population level impacts is poorly understood. Synthesis and Applications Behavioural response studies have greatly enhanced our understanding of the potential effects of navy sonar on marine mammals. Despite data gaps, we believe a dose-response approach within a risk-disturbance framework will enhance our ability to predict responsiveness for unstudied species and populations. We advocate for (1) regulatory frameworks to utilise recent peer-reviewed research findings when making predictions of impact (where feasible within assessment cycles), (2) regulatory frameworks to account for the inherent uncertainty in predictions of impact, and (3) investment in monitoring programmes that are both directed by recent research and offer opportunities for validation of predictions at the individual and population level.
This manuscript was written following the Behavioral Response Research Evaluation Workshop (BRREW), jointly sponsored by the US Office of Naval Research, US Navy Living Marine Resources, and US National Oceanic and Atmospheric Administration - National Marine Fisheries Service. PLT acknowledges funding from the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland). MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions.
Mon, 01 Jan 2018 00:00:00 GMThttp://hdl.handle.net/10023/112592018-01-01T00:00:00ZHarris, Catriona MThomas, LenFalcone, ErinHildebrand, JohnHouser, DorianKvadsheim, PetterLam, Frans-Peter A.Miller, PatrickMoretti, David J.Read, AndrewSlabbekoorn, HansSouthall, Brandon L.Tyack, Peter LloydWartzok, DouglasJanik, Vincent M.1. Marine mammals may be negatively affected by anthropogenic noise. Behavioural response studies (BRSs) aim to establish a relationship between the exposure dose of a stressor and associated behavioural responses of animals. A recent series of BRSs have focused on the effects of naval sonar on cetaceans. Here we review the current state of understanding of the impact of sonar on marine mammals and highlight knowledge gaps and future research priorities. 2. Many marine mammal species exhibit responses to naval sonar. However, responses are highly variable between and within individuals, species and populations, highlighting the importance of context in modulating dose-response relationships. 3. There is increasing support for the risk-disturbance hypothesis as an underlying response mechanism. This hypothesis proposes that sonar sounds may be perceived by animals as a threat, evoking an evolved anti-predator response. An understanding of responses within both the dose-response and risk-disturbance frameworks may enhance our ability to predict responsiveness for unstudied species and populations. 4. Many observed behavioural responses are energetically costly, but the way in which these responses may lead to long-term individual and population level impacts is poorly understood. Synthesis and Applications Behavioural response studies have greatly enhanced our understanding of the potential effects of navy sonar on marine mammals. Despite data gaps, we believe a dose-response approach within a risk-disturbance framework will enhance our ability to predict responsiveness for unstudied species and populations. We advocate for (1) regulatory frameworks to utilise recent peer-reviewed research findings when making predictions of impact (where feasible within assessment cycles), (2) regulatory frameworks to account for the inherent uncertainty in predictions of impact, and (3) investment in monitoring programmes that are both directed by recent research and offer opportunities for validation of predictions at the individual and population level.Tracking the kinematics of caudal-oscillatory swimming : a comparison of two on-animal sensing methodshttp://hdl.handle.net/10023/11257
Studies of locomotion kinematics require high-resolution information about body movements and the specific acceleration (SA) that these generate. On-animal accelerometers measure both orientation and SA but an additional orientation sensor is needed to accurately separate these. Although gyroscopes can perform this function, their power consumption, drift and complex data processing make them unattractive for biologging. Lower power magnetometers can also be used with some limitations. Here, we present an integrated and simplified method for estimating body rotations and SA applicable to both gyroscopes and magnetometers, enabling a direct comparison of these two sensors. We use a tag with both sensors to demonstrate how caudal-oscillation rate and SA are adjusted by a diving whale in response to rapidly changing buoyancy forces as the lungs compress while descending. Both sensors gave similar estimates of the dynamic forces demonstrating that magnetometers may offer a simpler low-power alternative for miniature tags in some applications.
Funding: Marie Sklodowska Curie Career Integration Grant and by The Marine Alliance for Science and Technology for Scotland (MASTS).
Fri, 01 Jul 2016 00:00:00 GMThttp://hdl.handle.net/10023/112572016-07-01T00:00:00ZMartin Lopez, Lucia MartinaAguilar de Soto, NatachaMiller, PatrickJohnson, MarkStudies of locomotion kinematics require high-resolution information about body movements and the specific acceleration (SA) that these generate. On-animal accelerometers measure both orientation and SA but an additional orientation sensor is needed to accurately separate these. Although gyroscopes can perform this function, their power consumption, drift and complex data processing make them unattractive for biologging. Lower power magnetometers can also be used with some limitations. Here, we present an integrated and simplified method for estimating body rotations and SA applicable to both gyroscopes and magnetometers, enabling a direct comparison of these two sensors. We use a tag with both sensors to demonstrate how caudal-oscillation rate and SA are adjusted by a diving whale in response to rapidly changing buoyancy forces as the lungs compress while descending. Both sensors gave similar estimates of the dynamic forces demonstrating that magnetometers may offer a simpler low-power alternative for miniature tags in some applications.Discrimination of fast click series produced by tagged Risso’s dolphins (Grampus griseus) for echolocation or communicationhttp://hdl.handle.net/10023/11171
Early studies that categorized odontocete pulsed sounds had few means of discriminating signals used for biosonar-based foraging from those used for communication. This capability to identify the function of sounds is important for understanding and interpreting behavior; it is also essential for monitoring and mitigating potential disturbance from human activities. Archival tags were placed on free-ranging Grampus griseus to quantify and discriminate between pulsed sounds used for echolocation-based foraging and those used for communication. Two types of rapid click-series pulsed sounds, buzzes and burst pulses, were identified as produced by the tagged dolphins and classified using a Gaussian mixture model based on their duration, association with jerk (i.e., rapid change of acceleration), and temporal association with click trains. Buzzes followed regular echolocation clicks and coincided with a strong jerk signal from accelerometers on the tag. They consisted of series averaging 359 ± 210 (mean ± SD) clicks with an increasing repetition rate and relatively low amplitude. Burst pulses consisted of relatively short click series averaging 45 ± 54 clicks with decreasing repetition rate and longer inter-click interval that were less likely to be associated with regular echolocation and the jerk signal. These results suggest that the longer, relatively lower amplitude, jerk-associated buzzes are used in this species to capture prey, mostly during the bottom phase of foraging dives, as seen in other odontocetes. In contrast, the shorter, isolated burst pulses that are generally emitted by the dolphins while at or near the surface are used outside of a direct, known foraging context.
This work was supported by the US Navy through several grants and contracts including grants and contracts from the Office of the Chief of Naval Operations, Environmental Readiness Program, U.S. Navy, Living Marine Resources Program, and the U.S. Office of Naval Research Marine Mammal Program (to both the SOCAL-BRS and MOCHA (Multi-study ocean acoustics human effects analysis) projects). Additional support was provided by the MASTS pooling initiative (Marine Alliance for Science and Technology for Scotland; supported by the Scottish Funding Council (grant reference HR09011) and contributing institutions).
Wed, 21 Sep 2016 00:00:00 GMThttp://hdl.handle.net/10023/111712016-09-21T00:00:00ZArranz Alonso, P.DeRuiter, S. L.Stimpert, A. K.Neves, SilvanaFriedlaender, A. S.Goldbogen, J. A.Visser, F.Calambokidis, J.Southall, B. L.Tyack, P. L.Early studies that categorized odontocete pulsed sounds had few means of discriminating signals used for biosonar-based foraging from those used for communication. This capability to identify the function of sounds is important for understanding and interpreting behavior; it is also essential for monitoring and mitigating potential disturbance from human activities. Archival tags were placed on free-ranging Grampus griseus to quantify and discriminate between pulsed sounds used for echolocation-based foraging and those used for communication. Two types of rapid click-series pulsed sounds, buzzes and burst pulses, were identified as produced by the tagged dolphins and classified using a Gaussian mixture model based on their duration, association with jerk (i.e., rapid change of acceleration), and temporal association with click trains. Buzzes followed regular echolocation clicks and coincided with a strong jerk signal from accelerometers on the tag. They consisted of series averaging 359 ± 210 (mean ± SD) clicks with an increasing repetition rate and relatively low amplitude. Burst pulses consisted of relatively short click series averaging 45 ± 54 clicks with decreasing repetition rate and longer inter-click interval that were less likely to be associated with regular echolocation and the jerk signal. These results suggest that the longer, relatively lower amplitude, jerk-associated buzzes are used in this species to capture prey, mostly during the bottom phase of foraging dives, as seen in other odontocetes. In contrast, the shorter, isolated burst pulses that are generally emitted by the dolphins while at or near the surface are used outside of a direct, known foraging context.The significance of respiration timing in the energetics estimates of free-ranging killer whales (Orcinus orca)http://hdl.handle.net/10023/11163
Respiration rate has been used as an indicator of metabolic rates and associated cost-of-transport (COT) of free-ranging cetaceans, discounting potential respiration-by-respiration variation in O2 uptake. To investigate the influence of respiration timing on O2 uptake we developed a dynamic model of O2 exchange and storage. Individual respiration events were revealed from kinematic data from ten adult Norwegian herring-feeding killer whales (Orcinus orca) recorded with high-resolution tags (DTAGs). We compared fixed-O2-uptake-per-respiration models to O2 uptake per respiration estimated through a simple 'broken-stick' O2-uptake function, in which O2 uptake was assumed to be the maximum-possible O2 uptake when stores are depleted or maximum total body O2 store minus existing O2 store when stores are close to saturated. Conversely to assuming fixed O2 uptake per respiration, uptake from the broken-stick model yielded a high correlation (r2 > 0.9) between O2 uptake and activity level. Moreover, we found that respiration intervals became less variable and increased at higher swimming speeds, possibly to increase O2 uptake efficiency per breath. As found in previous studies, COT decreased monotonically versus speed using the fixed-O2-uptake-per-respiration models. However, the broken-stick uptake model yielded a curvilinear COT-curve with a clear minimum at typical swimming speeds of 1.7-2.4 m s-1. Our results showed that respiration-by-respiration variation in O2 uptake is significant. And though O2 consumption measurements of COT for free-ranging cetaceans remain impractical, accounting for the influence of respiration timing on O2 uptake will lead to more consistent predictions of field metabolic rates than using respiration rate alone.
Fri, 01 Jul 2016 00:00:00 GMThttp://hdl.handle.net/10023/111632016-07-01T00:00:00ZRoos, Marjoleine Merel HansjeWu, Gi-MickMiller, PatrickRespiration rate has been used as an indicator of metabolic rates and associated cost-of-transport (COT) of free-ranging cetaceans, discounting potential respiration-by-respiration variation in O2 uptake. To investigate the influence of respiration timing on O2 uptake we developed a dynamic model of O2 exchange and storage. Individual respiration events were revealed from kinematic data from ten adult Norwegian herring-feeding killer whales (Orcinus orca) recorded with high-resolution tags (DTAGs). We compared fixed-O2-uptake-per-respiration models to O2 uptake per respiration estimated through a simple 'broken-stick' O2-uptake function, in which O2 uptake was assumed to be the maximum-possible O2 uptake when stores are depleted or maximum total body O2 store minus existing O2 store when stores are close to saturated. Conversely to assuming fixed O2 uptake per respiration, uptake from the broken-stick model yielded a high correlation (r2 > 0.9) between O2 uptake and activity level. Moreover, we found that respiration intervals became less variable and increased at higher swimming speeds, possibly to increase O2 uptake efficiency per breath. As found in previous studies, COT decreased monotonically versus speed using the fixed-O2-uptake-per-respiration models. However, the broken-stick uptake model yielded a curvilinear COT-curve with a clear minimum at typical swimming speeds of 1.7-2.4 m s-1. Our results showed that respiration-by-respiration variation in O2 uptake is significant. And though O2 consumption measurements of COT for free-ranging cetaceans remain impractical, accounting for the influence of respiration timing on O2 uptake will lead to more consistent predictions of field metabolic rates than using respiration rate alone.Harbour Seal Decline - vital rates and drivers : Report to Scottish Government MMSS/002/15http://hdl.handle.net/10023/11152
Numbers of harbour seals (Phoca vitulina) have dramatically declined in several regions of the north and east of Scotland, while numbers have remained stable or have increased in regions on the west coast. For any management and mitigation plans to address this situation, the relative contribution of various factors in the decline of harbour seals in Scotland needs to be identified, understood and assessed. Potential drivers of the decline include changes in prey quality and/or availability, increasing grey seal population size which may be influencing harbour seal populations through direct predation or competition for prey resources, and the occurrence and exposure of seals to toxins from harmful algae. Previous work by Matthiopoulos et al. (2014) and Caillat and Smout (2015) developed and fitted an age-structured population model to data from the well-studied subpopulation of harbour seals in Loch Fleet (Moray Firth), to evaluate the contributions of different potential proximate causes to the observed decline. After reviewing the existing software, this model has been re-coded directly into R, a framework that will allow for future development and maintenance, and has been designed to be adapted to different model structures and future data sets. Preliminary results are consistent with those obtained from the original OpenBUGS modelling. Future work will have as its key objective the identification of the important drivers of population change in harbour seals, from those being studied as listed above. Temporal and spatial variation in these drivers will be incorporated into the population model. Harbour seal haulout sites located in different regions of Scotland were visited in the spring and the summer of 2015 to collect information on their suitability for long-term monitoring of harbour seal populations, including their suitability for live captures, scat sampling, aerial and ground survey counts during pupping and moulting and photo-identification. This will allow empirical data to be collected and vital rates (fecundity and survival) to be estimated, for inclusion in the population model. A haulout site located in West Burray (Orkney) has been selected to represent a region of decline, and a haulout site by Peninver (East Kintyre) has been selected to represent a region of stability or increase. In addition, photo-identification data will also be collected in Dunvegan Loch (Isle of Skye). The regional scope of local populations at each study site (Orkney, Kintyre and Isle of Skye) has been defined to direct future collation of any relevant environmental and biological data. Existing aerial survey counts of harbour and grey seals at each of the defined areas have been collated for use in the age-structured population model. As part of the live captures programme, female harbour seals will be fitted in 2016 with low-cost electronic location tags, developed to allow a larger number of captured seals to be tagged and designed to regularly relay GPS locations from terrestrial locations. Data from these tags and from ten SMRU GPS/GSM phone tags will inform and direct the extent of the photo-identification re-sighting effort at haulout sites in 2016. Domoic acid (DA) concentrations have been measured in urine and faecal samples collected from harbour seals in 2015, as a continuation of the work carried out by Jensen et al. (2015). DA is still being found in harbour seals around the Scottish coast and whilst concentrations vary between the different matrices (blood, faeces and urine) and samples, due to variation in exposure and time from uptake to excretion, some individuals appear to be consuming relatively high levels of toxin. Data from the monitoring of biotoxins in shellfish by the Centre for Fisheries and Aquaculture Science (Cefas) and Harmful Algal Blooms (HABs) by the Scottish Association for Marine Science (SAMS) were available for all of 2015 and January 2016. These datasets provide some indication of the occurrence of HABs and toxin-producing blooms in the regions of interest. To further improve understanding of potential drivers of population change, initial contacts have been made to investigate the availability of prey samples relevant to seals foraging from the study sites, as well as the availability of prey abundance data from long-term fish surveys in the different regions of interest. An update is provided on the current state of knowledge of the causes of spiral lacerations in seals based on necropsy results of stranded individuals since November 2014. Occurrences around Scotland are summarised along with objective assessments of the cause of the wound patterns, based on a weighted scoring system.
Wed, 01 Jun 2016 00:00:00 GMThttp://hdl.handle.net/10023/111522016-06-01T00:00:00ZArso Civil, MonicaSmout, Sophie CarolineDuck, Callan DavidMorris, ChristopherOnoufriou, JosephThompson, DavidBrownlow, AndrewDavison, NicholasCummings, CarolinePomeroy, PatrickMcConnell, Bernie JHall, Ailsa JaneNumbers of harbour seals (Phoca vitulina) have dramatically declined in several regions of the north and east of Scotland, while numbers have remained stable or have increased in regions on the west coast. For any management and mitigation plans to address this situation, the relative contribution of various factors in the decline of harbour seals in Scotland needs to be identified, understood and assessed. Potential drivers of the decline include changes in prey quality and/or availability, increasing grey seal population size which may be influencing harbour seal populations through direct predation or competition for prey resources, and the occurrence and exposure of seals to toxins from harmful algae. Previous work by Matthiopoulos et al. (2014) and Caillat and Smout (2015) developed and fitted an age-structured population model to data from the well-studied subpopulation of harbour seals in Loch Fleet (Moray Firth), to evaluate the contributions of different potential proximate causes to the observed decline. After reviewing the existing software, this model has been re-coded directly into R, a framework that will allow for future development and maintenance, and has been designed to be adapted to different model structures and future data sets. Preliminary results are consistent with those obtained from the original OpenBUGS modelling. Future work will have as its key objective the identification of the important drivers of population change in harbour seals, from those being studied as listed above. Temporal and spatial variation in these drivers will be incorporated into the population model. Harbour seal haulout sites located in different regions of Scotland were visited in the spring and the summer of 2015 to collect information on their suitability for long-term monitoring of harbour seal populations, including their suitability for live captures, scat sampling, aerial and ground survey counts during pupping and moulting and photo-identification. This will allow empirical data to be collected and vital rates (fecundity and survival) to be estimated, for inclusion in the population model. A haulout site located in West Burray (Orkney) has been selected to represent a region of decline, and a haulout site by Peninver (East Kintyre) has been selected to represent a region of stability or increase. In addition, photo-identification data will also be collected in Dunvegan Loch (Isle of Skye). The regional scope of local populations at each study site (Orkney, Kintyre and Isle of Skye) has been defined to direct future collation of any relevant environmental and biological data. Existing aerial survey counts of harbour and grey seals at each of the defined areas have been collated for use in the age-structured population model. As part of the live captures programme, female harbour seals will be fitted in 2016 with low-cost electronic location tags, developed to allow a larger number of captured seals to be tagged and designed to regularly relay GPS locations from terrestrial locations. Data from these tags and from ten SMRU GPS/GSM phone tags will inform and direct the extent of the photo-identification re-sighting effort at haulout sites in 2016. Domoic acid (DA) concentrations have been measured in urine and faecal samples collected from harbour seals in 2015, as a continuation of the work carried out by Jensen et al. (2015). DA is still being found in harbour seals around the Scottish coast and whilst concentrations vary between the different matrices (blood, faeces and urine) and samples, due to variation in exposure and time from uptake to excretion, some individuals appear to be consuming relatively high levels of toxin. Data from the monitoring of biotoxins in shellfish by the Centre for Fisheries and Aquaculture Science (Cefas) and Harmful Algal Blooms (HABs) by the Scottish Association for Marine Science (SAMS) were available for all of 2015 and January 2016. These datasets provide some indication of the occurrence of HABs and toxin-producing blooms in the regions of interest. To further improve understanding of potential drivers of population change, initial contacts have been made to investigate the availability of prey samples relevant to seals foraging from the study sites, as well as the availability of prey abundance data from long-term fish surveys in the different regions of interest. An update is provided on the current state of knowledge of the causes of spiral lacerations in seals based on necropsy results of stranded individuals since November 2014. Occurrences around Scotland are summarised along with objective assessments of the cause of the wound patterns, based on a weighted scoring system.Impact of wild prey availability on livestock predation by snow leopardshttp://hdl.handle.net/10023/11089
An increasing proportion of the world’s poor is rearing livestock today, and the global livestock population is growing. Livestock predation by large carnivores and their retaliatory killing is becoming an economic and conservation concern. A common recommendation for carnivore conservation and for reducing predation on livestock is to increase wild prey populations based on the assumption that the carnivores will consume this alternative food. Livestock predation, however, could either reduce or intensify with increases in wild prey depending on prey choice and trends in carnivore abundance. We show that the extent of livestock predation by the endangered snow leopard Panthera uncia intensifies with increases in the density of wild ungulate prey, and subsequently stabilizes. We found that snow leopard density, estimated at seven sites, was a positive linear function of the density of wild ungulates—the preferred prey—and showed no discernible relationship with livestock density. We also found that modelled livestock predation increased with livestock density. Our results suggest that snow leopard conservation would benefit from an increase in wild ungulates, but that would intensify the problem of livestock predation for pastoralists. The potential benefits of increased wild prey abundance in reducing livestock predation can be overwhelmed by a resultant increase in snow leopard populations. Snow leopard conservation efforts aimed at facilitating increases in wild prey must be accompanied by greater assistance for better livestock protection and offsetting the economic damage caused by carnivores.
The fieldwork was supported by Fondation Segré-Whitley Fund for Nature, Conservation Leadership Programme and National Geographic Young Explorer fund. These grants supported K.R.S., Y.V.B. and C.M. Laboratory analysis was supported by the Department of Science and Technology, Government of India. This grant supported U.R., V.C., Y.V.B., K.R.S. and C.M. Data Dryad Repository. (http://dx.doi.org/10.5061/dryad.8p689)
Wed, 07 Jun 2017 00:00:00 GMThttp://hdl.handle.net/10023/110892017-06-07T00:00:00ZSuryawanshi, Kulbhushansingh R.Redpath, Stephen M.Bhatnagar, Yash VeerRamakrishnan, UmaChaturvedi, VaibhavSmout, Sophie C.Mishra, CharuduttAn increasing proportion of the world’s poor is rearing livestock today, and the global livestock population is growing. Livestock predation by large carnivores and their retaliatory killing is becoming an economic and conservation concern. A common recommendation for carnivore conservation and for reducing predation on livestock is to increase wild prey populations based on the assumption that the carnivores will consume this alternative food. Livestock predation, however, could either reduce or intensify with increases in wild prey depending on prey choice and trends in carnivore abundance. We show that the extent of livestock predation by the endangered snow leopard Panthera uncia intensifies with increases in the density of wild ungulate prey, and subsequently stabilizes. We found that snow leopard density, estimated at seven sites, was a positive linear function of the density of wild ungulates—the preferred prey—and showed no discernible relationship with livestock density. We also found that modelled livestock predation increased with livestock density. Our results suggest that snow leopard conservation would benefit from an increase in wild ungulates, but that would intensify the problem of livestock predation for pastoralists. The potential benefits of increased wild prey abundance in reducing livestock predation can be overwhelmed by a resultant increase in snow leopard populations. Snow leopard conservation efforts aimed at facilitating increases in wild prey must be accompanied by greater assistance for better livestock protection and offsetting the economic damage caused by carnivores.Harbour porpoise distribution can vary at small spatiotemporal scales in energetic habitatshttp://hdl.handle.net/10023/11068
Marine habitat heterogeneity underpins species distribution and can be generated through interactions between physical and biological drivers at multiple spatiotemporal scales. Passive acoustic monitoring (PAM) is used worldwide to study potential impacts of marine industrial activities on cetaceans, but understanding of animals’ site use at small spatiotemporal scales (<1 km, <1 day) remains limited. Small-scale variability in vocalising harbour porpoise (Phocoena phocoena) distribution within two Scottish marine renewable energy development (MRED) sites was investigated by deploying dense arrays of C-POD passive acoustic detectors at a wave energy test site (the European Marine Energy Centre [Billia Croo, Orkney]) and by a minor tidal-stream site (Scarba [Inner Hebrides]). Respective arrays consisted of 7 & 11 moorings containing two C-PODs each and were deployed for up to 55 days. Minimum inter-mooring distances varied between ~300–600 m. All C-POD data were analysed at a temporal resolution of whole minutes, with each minute classified as 1 or 0 on the basis of presence/absence of porpoise click trains (Porpoise-Positive Minutes/PPMs). Porpoise detection rates were analysed using Generalised Additive Models (GAMs) with Generalised Estimation Equations (GEEs). Although there were many porpoise detections (wave test site: N = 3,432; tidal-stream site: N = 17,366), daily detection rates varied significantly within both arrays. Within the wave site array (<1 km diameter), average daily detection rates varied from 4.3–14.8 PPMs/day. Within the tidal-stream array (<2 km diameter), average daily detection rates varied from 10.3–49.7 PPMs/day. GAM-GEE model results for individual moorings within both arrays indicated linkages between porpoise presence and small-scale heterogeneity among different environmental covariates (e.g. tidal phase, time of day). Porpoise detection rates varied considerably but with coherent patterns between moorings only several hundred metres apart and within hours. These patterns presumably have ecological relevance. These results indicate that, in energetically active and heterogeneous areas, porpoises can display significant spatiotemporal variability in site use at scales of hundreds of metres and hours. Such variability will not be identified when using solitary moored PAM detectors (a common practice for site-based cetacean monitoring), but may be highly relevant for site-based impact assessments of MRED and other coastal developments. PAM arrays encompassing several detectors spread across a site therefore appear to be a more appropriate tool to study site-specific cetacean use of spatiotemporally heterogeneous habitat and assess the potential impacts of coastal and nearshore developments at small scales.
The authors acknowledge support received from the Scottish Funding Council, Highlands & Islands Enterprise, Scottish Power Renewables and E.ON under the Hebridean Marine Energy Futures (HMEF) programme (Grant reference number 1R042 (HFU) SPIRIT , Project Ref. HR10012), a research initiative led by the University of the Highlands and Islands (UHI) and Aquamarine Power. Scarba C-POD data were collected under the UK Natural Environment Research Council (DEFRA/NERC) grant NE/J004367/1 (RESPONSE).
Sat, 01 Jul 2017 00:00:00 GMThttp://hdl.handle.net/10023/110682017-07-01T00:00:00ZBenjamins, Stevenvan Geel, NienkeHastie, GordonElliott, JimWilson, BenMarine habitat heterogeneity underpins species distribution and can be generated through interactions between physical and biological drivers at multiple spatiotemporal scales. Passive acoustic monitoring (PAM) is used worldwide to study potential impacts of marine industrial activities on cetaceans, but understanding of animals’ site use at small spatiotemporal scales (<1 km, <1 day) remains limited. Small-scale variability in vocalising harbour porpoise (Phocoena phocoena) distribution within two Scottish marine renewable energy development (MRED) sites was investigated by deploying dense arrays of C-POD passive acoustic detectors at a wave energy test site (the European Marine Energy Centre [Billia Croo, Orkney]) and by a minor tidal-stream site (Scarba [Inner Hebrides]). Respective arrays consisted of 7 & 11 moorings containing two C-PODs each and were deployed for up to 55 days. Minimum inter-mooring distances varied between ~300–600 m. All C-POD data were analysed at a temporal resolution of whole minutes, with each minute classified as 1 or 0 on the basis of presence/absence of porpoise click trains (Porpoise-Positive Minutes/PPMs). Porpoise detection rates were analysed using Generalised Additive Models (GAMs) with Generalised Estimation Equations (GEEs). Although there were many porpoise detections (wave test site: N = 3,432; tidal-stream site: N = 17,366), daily detection rates varied significantly within both arrays. Within the wave site array (<1 km diameter), average daily detection rates varied from 4.3–14.8 PPMs/day. Within the tidal-stream array (<2 km diameter), average daily detection rates varied from 10.3–49.7 PPMs/day. GAM-GEE model results for individual moorings within both arrays indicated linkages between porpoise presence and small-scale heterogeneity among different environmental covariates (e.g. tidal phase, time of day). Porpoise detection rates varied considerably but with coherent patterns between moorings only several hundred metres apart and within hours. These patterns presumably have ecological relevance. These results indicate that, in energetically active and heterogeneous areas, porpoises can display significant spatiotemporal variability in site use at scales of hundreds of metres and hours. Such variability will not be identified when using solitary moored PAM detectors (a common practice for site-based cetacean monitoring), but may be highly relevant for site-based impact assessments of MRED and other coastal developments. PAM arrays encompassing several detectors spread across a site therefore appear to be a more appropriate tool to study site-specific cetacean use of spatiotemporally heterogeneous habitat and assess the potential impacts of coastal and nearshore developments at small scales.Obtaining accurate glucose measurements from wild animals under field conditions : comparing a hand held glucometer with a standard laboratory technique in grey sealshttp://hdl.handle.net/10023/11054
Glucose is an important metabolic fuel and circulating levels are tightly regulated in most mammals, but can drop when body fuel reserves become critically low. Glucose is mobilized rapidly from liver and muscle during stress in response to increased circulating cortisol. Blood glucose levels can thus be of value in conservation as an indicator of nutritional status and may be a useful, rapid assessment marker for acute or chronic stress. However, seals show unusual glucose regulation: circulating levels are high and insulin sensitivity is limited. Accurate blood glucose measurement is therefore vital to enable meaningful health and physiological assessments in captive, wild or rehabilitated seals and to explore its utility as a marker of conservation relevance in these animals. Point-of-care devices are simple, portable, relatively cheap and use less blood compared with traditional sampling approaches, making them useful in conservation-related monitoring. We investigated the accuracy of a hand-held glucometer for ‘instant’ field measurement of blood glucose, compared with blood drawing followed by laboratory testing, in wild grey seals (Halichoerus grypus), a species used as an indicator for Good Environmental Status in European waters. The glucometer showed high precision, but low accuracy, relative to laboratory measurements, and was least accurate at extreme values. It did not provide a reliable alternative to plasma analysis. Poor correlation between methods may be due to suboptimal field conditions, greater and more variable haematocrit, faster erythrocyte settling rate and/or lipaemia in seals. Glucometers must therefore be rigorously tested before use in new species and demographic groups. Sampling, processing and glucose determination methods have major implications for conclusions regarding glucose regulation, and health assessment in seals generally, which is important in species of conservation concern and in development of circulating glucose as a marker of stress or nutritional state for use in management and monitoring.
This work was supported in part by National Capability funding to Sea Mammal Research Unit, University of St Andrews (Grant No. SMRU 1001) from the UK Natural Environment Research Council. L.M.T. was supported by internal funding from Plymouth University.
Mon, 27 Feb 2017 00:00:00 GMThttp://hdl.handle.net/10023/110542017-02-27T00:00:00ZBennett, Kimberley A.Turner, Lucy M.Millward, SebastianMoss, Simon E. W.Hall, Ailsa J.Glucose is an important metabolic fuel and circulating levels are tightly regulated in most mammals, but can drop when body fuel reserves become critically low. Glucose is mobilized rapidly from liver and muscle during stress in response to increased circulating cortisol. Blood glucose levels can thus be of value in conservation as an indicator of nutritional status and may be a useful, rapid assessment marker for acute or chronic stress. However, seals show unusual glucose regulation: circulating levels are high and insulin sensitivity is limited. Accurate blood glucose measurement is therefore vital to enable meaningful health and physiological assessments in captive, wild or rehabilitated seals and to explore its utility as a marker of conservation relevance in these animals. Point-of-care devices are simple, portable, relatively cheap and use less blood compared with traditional sampling approaches, making them useful in conservation-related monitoring. We investigated the accuracy of a hand-held glucometer for ‘instant’ field measurement of blood glucose, compared with blood drawing followed by laboratory testing, in wild grey seals (Halichoerus grypus), a species used as an indicator for Good Environmental Status in European waters. The glucometer showed high precision, but low accuracy, relative to laboratory measurements, and was least accurate at extreme values. It did not provide a reliable alternative to plasma analysis. Poor correlation between methods may be due to suboptimal field conditions, greater and more variable haematocrit, faster erythrocyte settling rate and/or lipaemia in seals. Glucometers must therefore be rigorously tested before use in new species and demographic groups. Sampling, processing and glucose determination methods have major implications for conclusions regarding glucose regulation, and health assessment in seals generally, which is important in species of conservation concern and in development of circulating glucose as a marker of stress or nutritional state for use in management and monitoring.Responses of bottlenose dolphins and harbor porpoises to impact and vibration piling noise during harbor constructionhttp://hdl.handle.net/10023/10877
The development of risk assessments for the exposure of protected populations to noise from coastal construction is constrained by uncertainty over the nature and extent of marine mammal responses to man-made noise. Stakeholder concern often focuses on the potential for local displacement caused by impact piling, where piles are hammered into the seabed. To mitigate this threat, use of vibration piling, where piles are shaken into place with a vibratory hammer, is often encouraged due to presumed impact reduction. However, data on comparative responses of cetaceans to these different noise sources are lacking. We studied the responses of bottlenose dolphins and harbor porpoises to both impact and vibration pile driving noise during harbor construction works in northeast Scotland, using passive acoustic monitoring devices to record cetacean activity and noise recorders to measure and predict received noise levels. Local abundance and patterns of occurrence of bottlenose dolphins were also compared with a five-year baseline. The median peak-to-peak source level estimated for impact piling was 240 dB re 1 μPa (single-pulse sound exposure level [SEL] 198 dB re 1 μPa2 s), and the r.m.s. source level for vibration piling was 192 dB re 1 μPa. Predicted received broadband SEL values 812 m from the piling site were markedly lower due to high propagation loss: 133.4 dB re 1 μPa2 s (impact) and 128.9 dB re 1 μPa2 s (vibration). Bottlenose dolphins and harbor porpoises were not excluded from sites in the vicinity of impact piling or vibration piling; nevertheless, some small effects were detected. Bottlenose dolphins spent a reduced period of time in the vicinity of construction works during both impact and vibration piling. The probability of occurrence of both cetacean species was also slightly less during periods of vibration piling. This work provides developers and managers with the first evidence of the comparative effects of vibration and impact piling on small cetaceans, enabling more informed risk assessments, policy frameworks, and mitigation plans. In particular, our results emphasize the need for better understanding of noise levels and behavioral responses to vibration piling before recommending its use to mitigate impact piling.
This project was funded through the DECC Offshore Energy Strategic Environmental Assessment Programme using equipment previously purchased by DECC, Scottish Government, Oil and Gas UK, COWRIE and Moray Offshore Renewables Ltd. Scottish Natural Heritage, Beatrice Offshore Windfarm Ltd., MORL, Marine Scotland, The Crown Estate and Highlands and Islands Enterprise all provided funding for photo-identification surveys. Data have been made available in the Dryad repository at https://doi.org/10.5061/dryad.g3603.
Mon, 01 May 2017 00:00:00 GMThttp://hdl.handle.net/10023/108772017-05-01T00:00:00ZGraham, IslaPirotta, EnricoMerchant, NathanFarcas, AdrianBarton, TimCheney, BarbaraHastie, Gordon D.Thompson, PaulThe development of risk assessments for the exposure of protected populations to noise from coastal construction is constrained by uncertainty over the nature and extent of marine mammal responses to man-made noise. Stakeholder concern often focuses on the potential for local displacement caused by impact piling, where piles are hammered into the seabed. To mitigate this threat, use of vibration piling, where piles are shaken into place with a vibratory hammer, is often encouraged due to presumed impact reduction. However, data on comparative responses of cetaceans to these different noise sources are lacking. We studied the responses of bottlenose dolphins and harbor porpoises to both impact and vibration pile driving noise during harbor construction works in northeast Scotland, using passive acoustic monitoring devices to record cetacean activity and noise recorders to measure and predict received noise levels. Local abundance and patterns of occurrence of bottlenose dolphins were also compared with a five-year baseline. The median peak-to-peak source level estimated for impact piling was 240 dB re 1 μPa (single-pulse sound exposure level [SEL] 198 dB re 1 μPa2 s), and the r.m.s. source level for vibration piling was 192 dB re 1 μPa. Predicted received broadband SEL values 812 m from the piling site were markedly lower due to high propagation loss: 133.4 dB re 1 μPa2 s (impact) and 128.9 dB re 1 μPa2 s (vibration). Bottlenose dolphins and harbor porpoises were not excluded from sites in the vicinity of impact piling or vibration piling; nevertheless, some small effects were detected. Bottlenose dolphins spent a reduced period of time in the vicinity of construction works during both impact and vibration piling. The probability of occurrence of both cetacean species was also slightly less during periods of vibration piling. This work provides developers and managers with the first evidence of the comparative effects of vibration and impact piling on small cetaceans, enabling more informed risk assessments, policy frameworks, and mitigation plans. In particular, our results emphasize the need for better understanding of noise levels and behavioral responses to vibration piling before recommending its use to mitigate impact piling.Separating underwater ambient noise from flow noise recorded on stereo acoustic tags attached to marine mammalshttp://hdl.handle.net/10023/10867
Sound-recording acoustic tags attached to marine animals are commonly used in behavioural studies. Measuring ambient noise is of interest to efforts to understand responses of marine mammals to anthropogenic underwater sound, or to assess their communication space. Noise of water flowing around the tag reflects the speed of the animal, but hinders ambient noise measurement. Here, we describe a correlation-based method for stereo acoustic tags to separate the relative contributions of flow and ambient noise. The uncorrelated part of the noise measured in digital acoustic recording tag (DTAG) recordings related well to swim speed of a humpback whale (Megaptera novaeangliae), thus providing a robust measure of flow noise over a wide frequency bandwidth. By removing measurements affected by flow noise, consistent ambient noise estimates were made for two killer whales (Orcinus orca) with DTAGs attached simultaneously. The method is applicable to any multi-channel acoustic tag, enabling application to a wide range of marine species.
A.M.v.B.B. and P.B. were funded by The Netherlands Ministry of Defence. Fieldwork efforts and support for P.M. and F.S. was provided by the US Office of Naval Research [award numbers N00014-08-1-0984 and N00014-10-1-0355]. P.W. received a PhD studentship with matched funding from The Netherlands Ministry of Defence (administered by The Netherlands Organisation for Applied Scientific Research, TNO) and UK Natural Environment Research Council [NE/J500276/1].
Wed, 03 Aug 2016 00:00:00 GMThttp://hdl.handle.net/10023/108672016-08-03T00:00:00Zvon Benda-Beckmann, Alexander M.Wensveen, Paul JacobusSamarra, Filipa I. P.Beerens, S. PeterMiller, Patrick J. O.Sound-recording acoustic tags attached to marine animals are commonly used in behavioural studies. Measuring ambient noise is of interest to efforts to understand responses of marine mammals to anthropogenic underwater sound, or to assess their communication space. Noise of water flowing around the tag reflects the speed of the animal, but hinders ambient noise measurement. Here, we describe a correlation-based method for stereo acoustic tags to separate the relative contributions of flow and ambient noise. The uncorrelated part of the noise measured in digital acoustic recording tag (DTAG) recordings related well to swim speed of a humpback whale (Megaptera novaeangliae), thus providing a robust measure of flow noise over a wide frequency bandwidth. By removing measurements affected by flow noise, consistent ambient noise estimates were made for two killer whales (Orcinus orca) with DTAGs attached simultaneously. The method is applicable to any multi-channel acoustic tag, enabling application to a wide range of marine species.Ultra-high foraging rates of harbor porpoises make them vulnerable to anthropogenic disturbancehttp://hdl.handle.net/10023/10866
Summary. The question of how individuals acquire and allocate resources to maximize fitness is central in evolutionary ecology. Basic information on prey selection, search effort, and capture rates are critical for understanding a predator’s role in its ecosystem and for predicting its response to natural and anthropogenic disturbance. Yet, for most marine species, foraging interactions cannot be observed directly. The high costs of thermoregulation in water require that small marine mammals have elevated energy intakes compared to similar-sized terrestrial mammals [1]. The combination of high food requirements and their position at the apex of most marine food webs may make small marine mammals particularly vulnerable to changes within the ecosystem [2–4], but the lack of detailed information about their foraging behavior often precludes an informed conservation effort. Here, we use high-resolution movement and prey echo recording tags on five wild harbor porpoises to examine foraging interactions in one of the most metabolically challenged cetacean species. We report that porpoises forage nearly continuously day and night, attempting to capture up to 550 small (3–10 cm) fish prey per hour with a remarkable prey capture success rate of >90%. Porpoises therefore target fish that are smaller than those of commercial interest, but must forage almost continually to meet their metabolic demands with such small prey, leaving little margin for compensation. Thus, for these “aquatic shrews,” even a moderate level of anthropogenic disturbance in the busy shallow waters they share with humans may have severe fitness consequences at individual and population levels.
This study was partly funded by the German Federal Agency for Nature Conservation (BfN) under the contract Z1.2-5330/2010/14 and the BfN-Cluster 7 “Effects of underwater noise on marine vertebrates.” D.M.W. and P.T.M. were also supported by the Danish National Research Foundation (FNU) and the Carlsberg Foundation, and M.J. was also supported by the Marine Alliance for Science and Technology Scotland (MASTS) and by a Marie Curie-Sklodowska award.
Mon, 06 Jun 2016 00:00:00 GMThttp://hdl.handle.net/10023/108662016-06-06T00:00:00ZWisniewska, Danuta MariaJohnson, MarkTeilmann, JonasRojano-Doñate, LaiaShearer, JeanneSveegaard, SigneMiller, Lee A.Siebert, UrsulaMadsen, Peter TeglbergSummary. The question of how individuals acquire and allocate resources to maximize fitness is central in evolutionary ecology. Basic information on prey selection, search effort, and capture rates are critical for understanding a predator’s role in its ecosystem and for predicting its response to natural and anthropogenic disturbance. Yet, for most marine species, foraging interactions cannot be observed directly. The high costs of thermoregulation in water require that small marine mammals have elevated energy intakes compared to similar-sized terrestrial mammals [1]. The combination of high food requirements and their position at the apex of most marine food webs may make small marine mammals particularly vulnerable to changes within the ecosystem [2–4], but the lack of detailed information about their foraging behavior often precludes an informed conservation effort. Here, we use high-resolution movement and prey echo recording tags on five wild harbor porpoises to examine foraging interactions in one of the most metabolically challenged cetacean species. We report that porpoises forage nearly continuously day and night, attempting to capture up to 550 small (3–10 cm) fish prey per hour with a remarkable prey capture success rate of >90%. Porpoises therefore target fish that are smaller than those of commercial interest, but must forage almost continually to meet their metabolic demands with such small prey, leaving little margin for compensation. Thus, for these “aquatic shrews,” even a moderate level of anthropogenic disturbance in the busy shallow waters they share with humans may have severe fitness consequences at individual and population levels.Positive social behaviours are induced and retained after oxytocin manipulations mimicking endogenous concentrations in a wild mammalhttp://hdl.handle.net/10023/10837
The neuropeptide hormone oxytocin modulates numerous social and parental behaviours across a wide range of species, including humans. We conducted manipulation experiments on wild grey seals (Halichoerus grypus) to determine whether oxytocin increases proximity-seeking behaviour, which has previously been correlated with endogenous oxytocin concentrations in wild seal populations. Pairs of seals that had never met previously were given intravenous injections of 0.41 µg kg−1 oxytocin or saline and were observed for 1 h post-manipulation. The dose was designed to mimic endogenous oxytocin concentrations during the observation period, and is one of the lowest doses used to manipulate behaviour to date. Seals given oxytocin spent significantly more time in close proximity to each other, confirming that oxytocin causes conspecifics to seek others out and remain close to one another. Aggressive and investigative behaviours also significantly fell after oxytocin manipulations. Despite using a minimal oxytocin dose, pro-social behavioural changes unexpectedly persisted for 2 days despite rapid dose clearance from circulation post-injection. This study verifies that oxytocin promotes individuals staying together, demonstrating how the hormone can form positive feedback loops of oxytocin release following conspecific stimuli, increased motivation to remain in close proximity and additional oxytocin release from stimuli received while in close proximity.
This work was conducted as part of a PhD, funded by the Natural Environment Research Council (NERC), UK (grant number NE/H524930/1) and by SMRU Marine, St Andrews, UK. PPP and SDT were in receipt of NERC grant NE/G008930/1 during the work.
Wed, 31 May 2017 00:00:00 GMThttp://hdl.handle.net/10023/108372017-05-31T00:00:00ZRobinson, Kelly JoanneTwiss, Sean D.Hazon, NeilMoss, SimonPomeroy, PatrickThe neuropeptide hormone oxytocin modulates numerous social and parental behaviours across a wide range of species, including humans. We conducted manipulation experiments on wild grey seals (Halichoerus grypus) to determine whether oxytocin increases proximity-seeking behaviour, which has previously been correlated with endogenous oxytocin concentrations in wild seal populations. Pairs of seals that had never met previously were given intravenous injections of 0.41 µg kg−1 oxytocin or saline and were observed for 1 h post-manipulation. The dose was designed to mimic endogenous oxytocin concentrations during the observation period, and is one of the lowest doses used to manipulate behaviour to date. Seals given oxytocin spent significantly more time in close proximity to each other, confirming that oxytocin causes conspecifics to seek others out and remain close to one another. Aggressive and investigative behaviours also significantly fell after oxytocin manipulations. Despite using a minimal oxytocin dose, pro-social behavioural changes unexpectedly persisted for 2 days despite rapid dose clearance from circulation post-injection. This study verifies that oxytocin promotes individuals staying together, demonstrating how the hormone can form positive feedback loops of oxytocin release following conspecific stimuli, increased motivation to remain in close proximity and additional oxytocin release from stimuli received while in close proximity.Physical constraints of cultural evolution of dialects in killer whaleshttp://hdl.handle.net/10023/10796
Odontocete sounds are produced by two pairs of phonic lips situated in soft nares below the blowhole; the right pair is larger and is more likely to produce clicks, while the left pair is more likely to produce whistles. This has important implications for the cultural evolution of delphinid sounds: the greater the physical constraints, the greater the probability of random convergence. In this paper the authors examine the call structure of eight killer whale populations to identify structural constraints and to determine if they are consistent among all populations. Constraints were especially pronounced in two-voiced calls. In the calls of all eight populations, the lower component of two-voiced (biphonic) calls was typically centered below 4 kHz, while the upper component was typically above that value. The lower component of two-voiced calls had a narrower frequency range than single-voiced calls in all populations. This may be because some single-voiced calls are homologous to the lower component, while others are homologous to the higher component of two-voiced calls. Physical constraints on the call structure reduce the possible variation and increase the probability of random convergence, producing similar calls in different populations.
Data collection was supported by a variety of organizations, including the Russian Fund for the Fundamental Research (Grant No. 15-04-05540), the Rufford Small Grants Fund, Whale and Dolphin Conservation, the Fundação para a Ciência e a Tecnologia (Grant No. SFRH/BD/30303/2006), Russell Trust Award of the University of St. Andrews, the Office of Naval Research, the Icelandic Research Fund (i. Rannsóknasjóður), the National Geographic Society Science and Exploration Europe (Grant No. GEFNE65-12), Vancouver Aquarium Marine Science Centre, the Canadian Ministry of Fisheries and Oceans, and the North Gulf Oceanic Society.
Thu, 17 Nov 2016 00:00:00 GMThttp://hdl.handle.net/10023/107962016-11-17T00:00:00ZFilatova, Olga A.Samarra, Filipa I. P.Barrett-Lennard, Lance G.Miller, Patrick J. O.Ford, John K. B.Yurk, HaraldMatkin, Craig O.Hoyt, ErichOdontocete sounds are produced by two pairs of phonic lips situated in soft nares below the blowhole; the right pair is larger and is more likely to produce clicks, while the left pair is more likely to produce whistles. This has important implications for the cultural evolution of delphinid sounds: the greater the physical constraints, the greater the probability of random convergence. In this paper the authors examine the call structure of eight killer whale populations to identify structural constraints and to determine if they are consistent among all populations. Constraints were especially pronounced in two-voiced calls. In the calls of all eight populations, the lower component of two-voiced (biphonic) calls was typically centered below 4 kHz, while the upper component was typically above that value. The lower component of two-voiced calls had a narrower frequency range than single-voiced calls in all populations. This may be because some single-voiced calls are homologous to the lower component, while others are homologous to the higher component of two-voiced calls. Physical constraints on the call structure reduce the possible variation and increase the probability of random convergence, producing similar calls in different populations.Resolving issues with environmental impact assessment of marine renewable energy installationshttp://hdl.handle.net/10023/10776
Growing concerns about climate change and energy security have fueled a rapid increase in the development of marine renewable energy installations (MREIs). The potential ecological consequences of increased use of these devices emphasizes the need for high quality environmental impact assessment (EIA). We demonstrate that these processes are hampered severely, primarily because ambiguities in the legislation and lack of clear implementation guidance are such that they do not ensure robust assessment of the significance of impacts and cumulative effects. We highlight why the regulatory framework leads to conceptual ambiguities and propose changes which, for the most part, do not require major adjustments to standard practice. We emphasize the importance of determining the degree of confidence in impacts to permit the likelihood as well as magnitude of impacts to be quantified and propose ways in which assessment of population-level impacts could be incorporated into the EIA process. Overall, however, we argue that, instead of trying to ascertain which particular developments are responsible for tipping an already heavily degraded marine environment into an undesirable state, emphasis should be placed on better strategic assessment.
Tue, 16 Dec 2014 00:00:00 GMThttp://hdl.handle.net/10023/107762014-12-16T00:00:00ZMaclean, Ilya M. D.Inger, RichardBenson, DavidBooth, Cormac G.Embling, Clare B.Grecian, W. JamesHeymans, Johanna J.Plummer, Kate E.Shackshaft, MichaelSparling, Carol E.Wilson, BenWright, Lucy J.Bradbury, GarethChristen, NadjaGodley, Brendan J.Jackson, Angus C.McCluskie, AlyNicholls-Lee, RachelBearhop, StuartGrowing concerns about climate change and energy security have fueled a rapid increase in the development of marine renewable energy installations (MREIs). The potential ecological consequences of increased use of these devices emphasizes the need for high quality environmental impact assessment (EIA). We demonstrate that these processes are hampered severely, primarily because ambiguities in the legislation and lack of clear implementation guidance are such that they do not ensure robust assessment of the significance of impacts and cumulative effects. We highlight why the regulatory framework leads to conceptual ambiguities and propose changes which, for the most part, do not require major adjustments to standard practice. We emphasize the importance of determining the degree of confidence in impacts to permit the likelihood as well as magnitude of impacts to be quantified and propose ways in which assessment of population-level impacts could be incorporated into the EIA process. Overall, however, we argue that, instead of trying to ascertain which particular developments are responsible for tipping an already heavily degraded marine environment into an undesirable state, emphasis should be placed on better strategic assessment.Inter- and intra-year variation in foraging areas of breeding kittiwakes (Rissa tridactyla)http://hdl.handle.net/10023/10775
While seabird conservation efforts have largely focused on protection from threats at the colony (e.g. reducing disturbance and predation), attention is increasingly being given to implementing protection measures for foraging areas at sea. For this to be effective, important foraging areas must be identified. Although numerous studies have examined seabird foraging behaviour, information is still lacking on the variability in area utilisation within and among breeding seasons. GPS devices were attached to adult black-legged kittiwakes breeding at an expanding North Sea colony (55°20′N, 1°32′W) during both incubation and chick-rearing in 2012 and during chick-rearing in 2011, to determine whether foraging areas remained consistent and to identify the oceanographic characteristics of areas used for foraging. The type and size of prey items consumed at different stages of the breeding cycle was also examined. During incubation (April-May 2012), kittiwakes foraged substantially further from the colony and fed on larger sandeels than when feeding chicks, and there was significant inter-annual variation in foraging areas used during the chick-rearing period (June-July 2011 and 2012). Foraging areas were characterised by cooler sea surface temperatures and areas of high chlorophyll a concentration, although association with specific oceanographic features changed within the breeding season and between years. These results emphasise the importance of considering how foraging areas and reliance on specific oceanographic conditions change over time when seeking to identify important marine areas for seabirds.
This work was supported by the National Environment Research Council (award number NE/I528369/1) and the Royal Society for the Protection of Birds through a CASE studentship to the University of Glasgow.
Mon, 01 Sep 2014 00:00:00 GMThttp://hdl.handle.net/10023/107752014-09-01T00:00:00ZRobertson, G. S.Bolton, M.Grecian, W. J.Monaghan, P.While seabird conservation efforts have largely focused on protection from threats at the colony (e.g. reducing disturbance and predation), attention is increasingly being given to implementing protection measures for foraging areas at sea. For this to be effective, important foraging areas must be identified. Although numerous studies have examined seabird foraging behaviour, information is still lacking on the variability in area utilisation within and among breeding seasons. GPS devices were attached to adult black-legged kittiwakes breeding at an expanding North Sea colony (55°20′N, 1°32′W) during both incubation and chick-rearing in 2012 and during chick-rearing in 2011, to determine whether foraging areas remained consistent and to identify the oceanographic characteristics of areas used for foraging. The type and size of prey items consumed at different stages of the breeding cycle was also examined. During incubation (April-May 2012), kittiwakes foraged substantially further from the colony and fed on larger sandeels than when feeding chicks, and there was significant inter-annual variation in foraging areas used during the chick-rearing period (June-July 2011 and 2012). Foraging areas were characterised by cooler sea surface temperatures and areas of high chlorophyll a concentration, although association with specific oceanographic features changed within the breeding season and between years. These results emphasise the importance of considering how foraging areas and reliance on specific oceanographic conditions change over time when seeking to identify important marine areas for seabirds.Quantifying variation in δ13C and δ15N isotopes within and between feathers and individuals : is one sample enough?http://hdl.handle.net/10023/10774
Studies of avian migration increasingly use stable isotope analysis to provide vital trophic and spatial markers. However, when interpreting differences in stable isotope values of feathers, many studies are forced to make assumptions about the timing of moult. A fundamental question remains about the consistency of these values within and between feathers from the same individual. In this study, we examine variation in carbon and nitrogen isotopes by sub-sampling feathers collected from the wings of adults of two small congeneric petrel species, the broad-billed Pachyptila vittata and Antarctic prion P. desolata. Broad-billed prion feather vane material was enriched in 15N compared to feather rachis material, but there was no detectable difference in δ13C. Comparison of multiple samples taken from Antarctic prion feathers indicated subtle difference in isotopes; rachis material was enriched in 13C compared to vane material, and there were differences along the length of the feather, with samples from the middle and tip of the feather depleted in 15N compared to those from the base. While the greatest proportion of model variance was explained by differences between feathers and individuals, the magnitude of these within-feather differences was up to 0.5 ‰ in δ15N and 0.8 ‰ in δ13C. We discuss the potential drivers of these differences, linking isotopic variation to individual-level dietary differences, movement patterns and temporal dietary shifts. A novel result is that within-feather differences in δ13C may be attributed to differences in keratin structure within feathers, suggesting further work is required to understand the role of different amino acids. Our results highlight the importance of multiple sampling regimes that consider both within- and between-feather variation in studies using stable isotopes.
This study represents a contribution to the ecosystems component of the British Antarctic Survey Polar Science for Planet Earth Programme, funded by The Natural Environment Research Council and through a NERC standard grant NE/I02237X/1.
Wed, 01 Apr 2015 00:00:00 GMThttp://hdl.handle.net/10023/107742015-04-01T00:00:00ZGrecian, W. JamesMcGill, Rona A. R.Phillips, Richard A.Ryan, Peter G.Furness, Robert W.Studies of avian migration increasingly use stable isotope analysis to provide vital trophic and spatial markers. However, when interpreting differences in stable isotope values of feathers, many studies are forced to make assumptions about the timing of moult. A fundamental question remains about the consistency of these values within and between feathers from the same individual. In this study, we examine variation in carbon and nitrogen isotopes by sub-sampling feathers collected from the wings of adults of two small congeneric petrel species, the broad-billed Pachyptila vittata and Antarctic prion P. desolata. Broad-billed prion feather vane material was enriched in 15N compared to feather rachis material, but there was no detectable difference in δ13C. Comparison of multiple samples taken from Antarctic prion feathers indicated subtle difference in isotopes; rachis material was enriched in 13C compared to vane material, and there were differences along the length of the feather, with samples from the middle and tip of the feather depleted in 15N compared to those from the base. While the greatest proportion of model variance was explained by differences between feathers and individuals, the magnitude of these within-feather differences was up to 0.5 ‰ in δ15N and 0.8 ‰ in δ13C. We discuss the potential drivers of these differences, linking isotopic variation to individual-level dietary differences, movement patterns and temporal dietary shifts. A novel result is that within-feather differences in δ13C may be attributed to differences in keratin structure within feathers, suggesting further work is required to understand the role of different amino acids. Our results highlight the importance of multiple sampling regimes that consider both within- and between-feather variation in studies using stable isotopes.Standardising home range studies towards improved management of the critically endangered black rhinoceroshttp://hdl.handle.net/10023/10729
Comparisons of recent estimations of home range sizes for the critically endangered black rhinoceros in Hluhluwe-iMfolozi Park (HiP), South Africa, with historical estimates led reports of a substantial (54%) increase, attributed to over-stocking and habitat deterioration that has far-reaching implications for rhino conservation. Other reports, however, suggest the increase is more likely an artefact caused by applying various home range estimators to non-standardised datasets. We collected 1939 locations of 25 black rhino over six years (2004–2009) to estimate annual home ranges and evaluate the hypothesis that they have increased in size. A minimum of 30 and 25 locations were required for accurate 95% MCP estimation of home range of adult rhinos, during the dry and wet seasons respectively. Forty and 55 locations were required for adult female and male annual MCP home ranges, respectively, and 30 locations were necessary for estimating 90% bivariate kernel home ranges accurately. Average annual 95% bivariate kernel home ranges were 20.4 ± 1.2 km2, 53 ±1.9% larger than 95% MCP ranges (9.8 km2 ± 0.9). When home range techniques used during the late-1960s in HiP were applied to our dataset, estimates were similar, indicating that ranges have not changed substantially in 50 years. Inaccurate, non-standardised, home range estimates and their comparison have the potential to mislead black rhino population management. We recommend that more care be taken to collect adequate numbers of rhino locations within standardized time periods (i.e., season or year) and that the comparison of home ranges estimated using dissimilar procedures be avoided. Home range studies of black rhino have been data deficient and procedurally inconsistent. Standardisation of methods is required.
Wed, 30 Mar 2016 00:00:00 GMThttp://hdl.handle.net/10023/107292016-03-30T00:00:00ZPlotz, Roan D.Grecian, W. JamesKerley, Graham I. H.Linklater, Wayne L.Comparisons of recent estimations of home range sizes for the critically endangered black rhinoceros in Hluhluwe-iMfolozi Park (HiP), South Africa, with historical estimates led reports of a substantial (54%) increase, attributed to over-stocking and habitat deterioration that has far-reaching implications for rhino conservation. Other reports, however, suggest the increase is more likely an artefact caused by applying various home range estimators to non-standardised datasets. We collected 1939 locations of 25 black rhino over six years (2004–2009) to estimate annual home ranges and evaluate the hypothesis that they have increased in size. A minimum of 30 and 25 locations were required for accurate 95% MCP estimation of home range of adult rhinos, during the dry and wet seasons respectively. Forty and 55 locations were required for adult female and male annual MCP home ranges, respectively, and 30 locations were necessary for estimating 90% bivariate kernel home ranges accurately. Average annual 95% bivariate kernel home ranges were 20.4 ± 1.2 km2, 53 ±1.9% larger than 95% MCP ranges (9.8 km2 ± 0.9). When home range techniques used during the late-1960s in HiP were applied to our dataset, estimates were similar, indicating that ranges have not changed substantially in 50 years. Inaccurate, non-standardised, home range estimates and their comparison have the potential to mislead black rhino population management. We recommend that more care be taken to collect adequate numbers of rhino locations within standardized time periods (i.e., season or year) and that the comparison of home ranges estimated using dissimilar procedures be avoided. Home range studies of black rhino have been data deficient and procedurally inconsistent. Standardisation of methods is required.Seabird diversity hotspot linked to ocean productivity in the Canary Current Large Marine Ecosystemhttp://hdl.handle.net/10023/10727
Upwelling regions are highly productive habitats targeted by wide-ranging marine predators and industrial fisheries. In this study, we track the migratory movements of eight seabird species from across the Atlantic; quantify overlap with the Canary Current Large Marine Ecosystem (CCLME) and determine the habitat characteristics that drive this association. Our results indicate the CCLME is a biodiversity hotspot for migratory seabirds; all tracked species and more than 70% of individuals used this upwelling region. Relative species richness peaked in areas where sea surface temperature averaged between 15 and 20°C, and correlated positively with chlorophyll a, revealing the optimum conditions driving bottom-up trophic effects for seabirds. Marine vertebrates are not confined by international boundaries, making conservation challenging. However, by linking diversity to ocean productivity, our research reveals the significance of the CCLME for seabird populations from across the Atlantic, making it a priority for conservation action.
Funding for this work was provided by the Peninsula Research Institute for Marine Renewable Energy, EU INTERREG project CHARM III, NERC (NE/G001014/1), MINECO CGL2013-42585-P, Defra's Darwin, Centre National de la Recherche Scientifique and Ligue Pour la Protection des Oiseaux within the EUINTERREG Project FAME (2009-1/089; 2010-2012).
Tue, 16 Aug 2016 00:00:00 GMThttp://hdl.handle.net/10023/107272016-08-16T00:00:00ZGrecian, W. JamesWitt, Matthew J.Attrill, Martin J.Bearhop, StuartBecker, Peter H.Egevang, CarstenFurness, Robert W.Godley, Brendan J.González-Solís, JacobGrémillet, DavidKopp, MatthiasLescroël, AmélieMatthiopoulos, JasonPatrick, Samantha C.Peter, Hans-UlrichPhillips, Richard A.Stenhouse, Iain J.Voltier, Stephen C.Upwelling regions are highly productive habitats targeted by wide-ranging marine predators and industrial fisheries. In this study, we track the migratory movements of eight seabird species from across the Atlantic; quantify overlap with the Canary Current Large Marine Ecosystem (CCLME) and determine the habitat characteristics that drive this association. Our results indicate the CCLME is a biodiversity hotspot for migratory seabirds; all tracked species and more than 70% of individuals used this upwelling region. Relative species richness peaked in areas where sea surface temperature averaged between 15 and 20°C, and correlated positively with chlorophyll a, revealing the optimum conditions driving bottom-up trophic effects for seabirds. Marine vertebrates are not confined by international boundaries, making conservation challenging. However, by linking diversity to ocean productivity, our research reveals the significance of the CCLME for seabird populations from across the Atlantic, making it a priority for conservation action.Contrasting migratory responses of two closely-related seabirds to long-term climate changehttp://hdl.handle.net/10023/10726
Many marine predators migrate between breeding and non-breeding areas to target resources that are seasonal but spatio-temporally predictable, and so are vulnerable to climate-induced changes in prey phenology and abundance. In the Southern Ocean, small petrels are major consumers, but perturbations in the ecosystem through ocean warming are altering food-web structure and have been linked to poleward shifts in the distribution of their cold-water zooplankton prey. In this study, we focused on 2 small congeneric petrels: the broad-billed prion Pachyptila vittata and the Antarctic prion P. desolata. Both are planktivorous, but the broad-billed prion specialises in feeding on large copepods. We investigated historical trends in non-breeding distribution by analysing feather stable isotope ratios from a time-series dating back to 1926, and examined contemporary non-breeding distributions of broad-billed prions tracked using miniaturised geolocation-immersion loggers. After controlling temporally for the Suess effect, we found that the δ13C signatures of Antarctic prions, but not broad-billed prions, declined during the study period. This suggests a southward shift in Antarctic prion non-breeding distribution over the last century. Both species exhibited significant declines in δ15N during the same period, indicative of long-term decreases in marine productivity in their moulting areas, or changes in the trophic structure of prey communities. Tracked broad-billed prions migrated ca. 1000 km to an area east of the breeding colony where the Louisville seamount chain bisects the subtropical front. Topographically driven upwellings are stable and predictable features and may be crucial in aggregating plankton. Targeting seamounts could therefore mitigate the impact of climate-induced prey shifts by providing refugia for the broad-billed prion.
Wed, 09 Nov 2016 00:00:00 GMThttp://hdl.handle.net/10023/107262016-11-09T00:00:00ZGrecian, W. JamesTaylor, Graeme A.Loh, GraemeMcGill, Rona A. R.Miskelly, Colin M.Phillips, Richard A.Thompson, David R.Furness, Robert W.Many marine predators migrate between breeding and non-breeding areas to target resources that are seasonal but spatio-temporally predictable, and so are vulnerable to climate-induced changes in prey phenology and abundance. In the Southern Ocean, small petrels are major consumers, but perturbations in the ecosystem through ocean warming are altering food-web structure and have been linked to poleward shifts in the distribution of their cold-water zooplankton prey. In this study, we focused on 2 small congeneric petrels: the broad-billed prion Pachyptila vittata and the Antarctic prion P. desolata. Both are planktivorous, but the broad-billed prion specialises in feeding on large copepods. We investigated historical trends in non-breeding distribution by analysing feather stable isotope ratios from a time-series dating back to 1926, and examined contemporary non-breeding distributions of broad-billed prions tracked using miniaturised geolocation-immersion loggers. After controlling temporally for the Suess effect, we found that the δ13C signatures of Antarctic prions, but not broad-billed prions, declined during the study period. This suggests a southward shift in Antarctic prion non-breeding distribution over the last century. Both species exhibited significant declines in δ15N during the same period, indicative of long-term decreases in marine productivity in their moulting areas, or changes in the trophic structure of prey communities. Tracked broad-billed prions migrated ca. 1000 km to an area east of the breeding colony where the Louisville seamount chain bisects the subtropical front. Topographically driven upwellings are stable and predictable features and may be crucial in aggregating plankton. Targeting seamounts could therefore mitigate the impact of climate-induced prey shifts by providing refugia for the broad-billed prion.Hidden Markov models reveal complexity in the diving behaviour of short-finned pilot whaleshttp://hdl.handle.net/10023/10632
Diving behaviour of short-finned pilot whales is often described by two states; deep foraging and shallow, non-foraging dives. However, this simple classification system ignores much of the variation that occurs during subsurface periods. We used multi-state hidden Markov models (HMM) to characterize states of diving behaviour and the transitions between states in short-finned pilot whales. We used three parameters (number of buzzes, maximum dive depth and duration) measured in 259 dives by digital acoustic recording tags (DTAGs) deployed on 20 individual whales off Cape Hatteras, North Carolina, USA. The HMM identified a four-state model as the best descriptor of diving behaviour. The state-dependent distributions for the diving parameters showed variation between states, indicative of different diving behaviours. Transition probabilities were considerably higher for state persistence than state switching, indicating that dive types occurred in bouts. Our results indicate that subsurface behaviour in short-finned pilot whales is more complex than a simple dichotomy of deep and shallow diving states, and labelling all subsurface behaviour as deep dives or shallow dives discounts a significant amount of important variation. We discuss potential drivers of these patterns, including variation in foraging success, prey availability and selection, bathymetry, physiological constraints and socially mediated behaviour.
This work was supported by award RC-2154 from the Strategic Environmental Research and Development Program and funding from the Naval Facilities Engineering Command Atlantic and NOAA Fisheries, Southeast Region. DS was supported by the United States Office of Naval Research grant N00014-12-1-0204, under the project entitled Multi-study Ocean acoustics Human effects Analysis (MOCHA).
Fri, 31 Mar 2017 00:00:00 GMThttp://hdl.handle.net/10023/106322017-03-31T00:00:00ZQuick, Nicola J.Isojunno, SaanaSadykova, DinaBowers, MatthewNowacek, Douglas P.Read, Andrew J.Diving behaviour of short-finned pilot whales is often described by two states; deep foraging and shallow, non-foraging dives. However, this simple classification system ignores much of the variation that occurs during subsurface periods. We used multi-state hidden Markov models (HMM) to characterize states of diving behaviour and the transitions between states in short-finned pilot whales. We used three parameters (number of buzzes, maximum dive depth and duration) measured in 259 dives by digital acoustic recording tags (DTAGs) deployed on 20 individual whales off Cape Hatteras, North Carolina, USA. The HMM identified a four-state model as the best descriptor of diving behaviour. The state-dependent distributions for the diving parameters showed variation between states, indicative of different diving behaviours. Transition probabilities were considerably higher for state persistence than state switching, indicating that dive types occurred in bouts. Our results indicate that subsurface behaviour in short-finned pilot whales is more complex than a simple dichotomy of deep and shallow diving states, and labelling all subsurface behaviour as deep dives or shallow dives discounts a significant amount of important variation. We discuss potential drivers of these patterns, including variation in foraging success, prey availability and selection, bathymetry, physiological constraints and socially mediated behaviour.A new approach to estimate fecundity rate from inter-birth intervalshttp://hdl.handle.net/10023/10627
Accurate estimates of fecundity rate are key to population assessments and effectively direct conservation efforts. We present a new approach to estimate fecundity rate based on the probability of a female giving birth, conditional on a previous birth t years ago, from which an expected inter-birth interval (IBI) can be estimated. We use generalized linear mixed-effects models to account for individual and temporal variability and apply the approach to individual reproductive histories of bottlenose dolphins (Tursiops truncatus) from the east coast of Scotland. We estimate a fecundity rate of 0.222 (95% CI = 0.218–0.253) and an expected IBI of 4.49 yr (95% CI = 3.94–4.93 yr). We use simulated data samples to show that the approach produces estimates with a minimum bias of <3%. Simulations are also used to investigate the effect of the most common data-driven biases in the estimates of birth intervals and fecundity rate; we recommend longitudinal studies of at least 10 yr and capture probabilities of at least 0.3 when using this methodology. The approach may be modified to incorporate other parameters of interest and should be applicable to any population with comprehensive data on birth intervals.
Funding for this work was provided by the Department of Energy and Climate Change (UK). Photo-identification data were collected during a series of grants and contracts from the BES, ASAB, Greenpeace Environmental Trust, Scottish Natural Heritage, Scottish Government, Whale and Dolphin Conservation, Talisman Energy (UK) Ltd., DECC, Chevron, and the Natural Environment Research Council.
Sat, 01 Apr 2017 00:00:00 GMThttp://hdl.handle.net/10023/106272017-04-01T00:00:00ZArso Civil, MònicaCheney, BarbaraQuick, Nicola J.Thompson, Paul M.Hammond, Philip S.Accurate estimates of fecundity rate are key to population assessments and effectively direct conservation efforts. We present a new approach to estimate fecundity rate based on the probability of a female giving birth, conditional on a previous birth t years ago, from which an expected inter-birth interval (IBI) can be estimated. We use generalized linear mixed-effects models to account for individual and temporal variability and apply the approach to individual reproductive histories of bottlenose dolphins (Tursiops truncatus) from the east coast of Scotland. We estimate a fecundity rate of 0.222 (95% CI = 0.218–0.253) and an expected IBI of 4.49 yr (95% CI = 3.94–4.93 yr). We use simulated data samples to show that the approach produces estimates with a minimum bias of <3%. Simulations are also used to investigate the effect of the most common data-driven biases in the estimates of birth intervals and fecundity rate; we recommend longitudinal studies of at least 10 yr and capture probabilities of at least 0.3 when using this methodology. The approach may be modified to incorporate other parameters of interest and should be applicable to any population with comprehensive data on birth intervals.Equity and career-life balance in marine mammal science?http://hdl.handle.net/10023/10613
It is widely acknowledged that family and care-giving responsibilities are driving women away from Science, Technology, Engineering, and Mathematics (STEM) fields. Marine mammal science often incurs heavy fieldwork and travel obligations, which make it a challenging career in which to find work-life balance. This opinion piece explores gender equality, equity (the principles of fairness that lead to equality), and work-life balance in science generally and in this field in particular. We aim to (1) raise awareness of these issues among members of the Society for Marine Mammalogy; (2) explore members’ attitudes and viewpoints collected from an online survey and further discussion at a biennial conference workshop in 2015; and (3) make suggestions for members to consider for action, or for the Board of Governors to consider in terms of changes to policy or procedures. Leaks in our pipeline—the attrition of women, and others with additional caring responsibilities—represent an intellectual and economic loss. By striving for equity and promoting work-life balance, we will help to ensure a healthy and productive Society better able to succeed in its aims promoting education, high quality research, conservation, and management of marine mammals.
Sat, 01 Jul 2017 00:00:00 GMThttp://hdl.handle.net/10023/106132017-07-01T00:00:00ZHooker, Sascha K.Simmons, Samantha E.Stimpert, Alison K.McDonald, Birgitte I.It is widely acknowledged that family and care-giving responsibilities are driving women away from Science, Technology, Engineering, and Mathematics (STEM) fields. Marine mammal science often incurs heavy fieldwork and travel obligations, which make it a challenging career in which to find work-life balance. This opinion piece explores gender equality, equity (the principles of fairness that lead to equality), and work-life balance in science generally and in this field in particular. We aim to (1) raise awareness of these issues among members of the Society for Marine Mammalogy; (2) explore members’ attitudes and viewpoints collected from an online survey and further discussion at a biennial conference workshop in 2015; and (3) make suggestions for members to consider for action, or for the Board of Governors to consider in terms of changes to policy or procedures. Leaks in our pipeline—the attrition of women, and others with additional caring responsibilities—represent an intellectual and economic loss. By striving for equity and promoting work-life balance, we will help to ensure a healthy and productive Society better able to succeed in its aims promoting education, high quality research, conservation, and management of marine mammals.Evaluating morphometric and metabolic markers of body condition in a small cetacean, the harbor porpoise (Phocoena phocoena)http://hdl.handle.net/10023/10598
Mammalian body condition is an important individual fitness metric as it affects both survival and reproductive success. The ability to accurately measure condition has key implications for predicting individual and population health, and therefore monitoring the population-level effects of changing environments. No consensus currently exists on the best measure to quantitatively estimate body condition in many species, including cetaceans. Here, two measures of body condition were investigated in the harbor porpoise (Phocoena phocoena). First, the most informative morphometric body condition index was identified. The mass/length2 ratio was the most appropriate morphometric index of 10 indices tested, explaining 50% of the variation in condition in stranded, male porpoises with different causes of death and across age classes (n = 291). Mass/length2 was then used to evaluate a second measure, blubber cortisol concentration, as a metabolic condition marker. Cortisol is the main glucocorticoid hormone involved in the regulation of lipolysis and overall energy balance in mammals, and concentrations could provide information on physiological state. Blubber cortisol concentrations did not significantly vary around the girth (n = 20), but there was significant vertical stratification through the blubber depth with highest concentrations in the innermost layer. Concentrations in the dorsal, outermost layer were representative of concentrations through the full blubber depth, showed variation by sex and age class, and were negatively correlated with mass/length2. Using this species as a model for live cetaceans from which standard morphometric measurements cannot be taken, but from which blubber biopsy samples are routinely collected, cortisol concentrations in the dorsal, outermost blubber layer could potentially be used as a biomarker of condition in free-ranging animals.
The authors would like to thank the funders; the Department for Environment Food and Rural Affairs (DEFRA) and Marine Scotland for a number of long term monitoring contracts awarded to the Scottish Marine Animal Strandings Scheme, the Sea Mammal Research Unit National Capability Funding from the Natural Environment Research Council (NERC) and the University of St. Andrews Masters in Marine Mammal Science program.
Mon, 01 May 2017 00:00:00 GMThttp://hdl.handle.net/10023/105982017-05-01T00:00:00ZKershaw, Joanna L.Sherrill, MeredithDavison, Nicholas J.Brownlow, AndrewHall, Ailsa J.Mammalian body condition is an important individual fitness metric as it affects both survival and reproductive success. The ability to accurately measure condition has key implications for predicting individual and population health, and therefore monitoring the population-level effects of changing environments. No consensus currently exists on the best measure to quantitatively estimate body condition in many species, including cetaceans. Here, two measures of body condition were investigated in the harbor porpoise (Phocoena phocoena). First, the most informative morphometric body condition index was identified. The mass/length2 ratio was the most appropriate morphometric index of 10 indices tested, explaining 50% of the variation in condition in stranded, male porpoises with different causes of death and across age classes (n = 291). Mass/length2 was then used to evaluate a second measure, blubber cortisol concentration, as a metabolic condition marker. Cortisol is the main glucocorticoid hormone involved in the regulation of lipolysis and overall energy balance in mammals, and concentrations could provide information on physiological state. Blubber cortisol concentrations did not significantly vary around the girth (n = 20), but there was significant vertical stratification through the blubber depth with highest concentrations in the innermost layer. Concentrations in the dorsal, outermost layer were representative of concentrations through the full blubber depth, showed variation by sex and age class, and were negatively correlated with mass/length2. Using this species as a model for live cetaceans from which standard morphometric measurements cannot be taken, but from which blubber biopsy samples are routinely collected, cortisol concentrations in the dorsal, outermost blubber layer could potentially be used as a biomarker of condition in free-ranging animals.Genetic population structure of harbour seals in the United Kingdom and neighbouring watershttp://hdl.handle.net/10023/10596
1. In the United Kingdom (UK), several harbour seal (Phoca vitulina) populations have been declining over the past decade. In order to understand the effect of these changes in abundance, this study seeks to determine the population structure of harbour seals in the UK, and in Scotland in particular, on a wider and finer spatial scale than has previously been reported. 2. Harbour seals were genotyped from 18 different localities throughout the UK and neighbouring localities in mainland Europe, at 12 microsatellite loci. Results from Bayesian and frequency based tests of population structure suggested an initial structural division into two main groups consisting of localities in northern UK and southern UK-mainland Europe, respectively. 3. These two clusters were further divided into four geographically distinct genetic clusters. 4. An overall agreement between the genetic results and the existing management areas for UK harbour seals was observed, but it is also clear that an adaptive management approach should be adopted, in which the delineation of the current management areas is maintained until further genetic and ecological information has been accumulated and analysed.
Natural Environment Research Council (GrantNumber(s): SMRU1001; Grant recipient(s): Ailsa Hall)
Tue, 01 Aug 2017 00:00:00 GMThttp://hdl.handle.net/10023/105962017-08-01T00:00:00ZOlsen, Morten TangeIslas, ValentinaGraves, Jeff A.Onoufriou, AubrieVincent, CecileBrasseur, SophieFrie, Anne KristineHall, Ailsa J.1. In the United Kingdom (UK), several harbour seal (Phoca vitulina) populations have been declining over the past decade. In order to understand the effect of these changes in abundance, this study seeks to determine the population structure of harbour seals in the UK, and in Scotland in particular, on a wider and finer spatial scale than has previously been reported. 2. Harbour seals were genotyped from 18 different localities throughout the UK and neighbouring localities in mainland Europe, at 12 microsatellite loci. Results from Bayesian and frequency based tests of population structure suggested an initial structural division into two main groups consisting of localities in northern UK and southern UK-mainland Europe, respectively. 3. These two clusters were further divided into four geographically distinct genetic clusters. 4. An overall agreement between the genetic results and the existing management areas for UK harbour seals was observed, but it is also clear that an adaptive management approach should be adopted, in which the delineation of the current management areas is maintained until further genetic and ecological information has been accumulated and analysed.Delphinid echolocation click detection probability on near-seafloor sensorshttp://hdl.handle.net/10023/10512
The probability of detecting echolocating delphinids on a near-seafloor sensor was estimated using two Monte Carlo simulation methods. One method estimated the probability of detecting a single click (cue counting); the other estimated the probability of detecting a group of delphinids (group counting). Echolocation click beam pattern and source level assumptions strongly influenced detectability predictions by the cue counting model. Group detectability was also influenced by assumptions about group behaviors. Model results were compared to in situ recordings of encounters with Risso's dolphin (Grampus griseus) and presumed pantropical spotted dolphin (Stenella attenuata) from a near-seafloor four-channel tracking sensor deployed in the Gulf of Mexico (25.537°N 84.632°W, depth 1220 m). Horizontal detection range, received level and estimated source level distributions from localized encounters were compared with the model predictions. Agreement between in situ results and model predictions suggests that simulations can be used to estimate detection probabilities when direct distance estimation is not available.
Funding for HARP data collection and analysis was provided by the Natural Resource Damage Assessment partners (20105138) and the Center for the Integrated Modeling and Analysis of the Gulf Ecosystem (C-IMAGE) Consortium of the BP/Gulf of Mexico Research Initiative (SA 12-10/GoMRI-007). The analyses and opinions expressed are those of the authors and not necessarily those of the funding entities. This research was made possible by a grant from The Gulf of Mexico Research Initiative/C-IMAGE II.
Thu, 01 Sep 2016 00:00:00 GMThttp://hdl.handle.net/10023/105122016-09-01T00:00:00ZFrasier, Kaitlin E.Wiggins, Sean M.Harris, DanielleMarques, Tiago A.Thomas, LenHildebrand, John A.The probability of detecting echolocating delphinids on a near-seafloor sensor was estimated using two Monte Carlo simulation methods. One method estimated the probability of detecting a single click (cue counting); the other estimated the probability of detecting a group of delphinids (group counting). Echolocation click beam pattern and source level assumptions strongly influenced detectability predictions by the cue counting model. Group detectability was also influenced by assumptions about group behaviors. Model results were compared to in situ recordings of encounters with Risso's dolphin (Grampus griseus) and presumed pantropical spotted dolphin (Stenella attenuata) from a near-seafloor four-channel tracking sensor deployed in the Gulf of Mexico (25.537°N 84.632°W, depth 1220 m). Horizontal detection range, received level and estimated source level distributions from localized encounters were compared with the model predictions. Agreement between in situ results and model predictions suggests that simulations can be used to estimate detection probabilities when direct distance estimation is not available.The Deepwater Horizon oil spill marine mammal injury assessmenthttp://hdl.handle.net/10023/10410
From 2010 to 2015, a team of scientists studied how the BP Deepwater Horizon (DWH) oil spill affected marine mammals inhabiting the northern Gulf of Mexico, as part of the DWH Natural Resource Damage Assessment process. The scientists conducted the assessment on behalf of the DWH co-Trustees, with the purpose of investigating whether marine mammals were exposed to DWH oil and what types of injuries they suffered as a result of the DWH oil exposure, and then quantifying those injuries to determine the appropriate amount of restoration required to offset the injuries. Photographs, aerial surveys, spatial analyses of the co-occurrence between surface slick and cetacean populations, and chemical fingerprinting of oiled and stranded carcasses all confirm that at least 15 cetacean species were exposed to the DWH surface slick. Cetaceans that encountered the slick likely inhaled, aspirated, ingested, and/or adsorbed oil. In this Theme Section, marine mammal biologists, statisticians, veterinarians, toxicologists, and epidemiologists describe and quantify the adverse effects of this oil exposure. Taken together, this combination of oil spill dynamics, veterinary assessments, pathological, spatial, and temporal analyses of stranded animals, stock identification techniques, population dynamics, and a broad set of coordinated modeling efforts is an unprecedented assessment of how a major oil spill impacted a large and complex marine mammal community and their connected habitats.
The studies described here were conducted as part of the DWH NRDA and included scientists funded through NOAA, other federal and state Trustees, and BP PLC. The John H. Prescott Marine Mammal Rescue Assistance Grant Program and the Marine Mammal Health and Stranding Response Program provided funding for this work in addition to the funding from the DWH NRDA.
Tue, 31 Jan 2017 00:00:00 GMThttp://hdl.handle.net/10023/104102017-01-31T00:00:00ZTakeshita, RyanSullivan, LaurieSmith, CynthiaCollier, TracyHall, AilsaBrosnan, TomRowles, TeriSchwacke, LoriFrom 2010 to 2015, a team of scientists studied how the BP Deepwater Horizon (DWH) oil spill affected marine mammals inhabiting the northern Gulf of Mexico, as part of the DWH Natural Resource Damage Assessment process. The scientists conducted the assessment on behalf of the DWH co-Trustees, with the purpose of investigating whether marine mammals were exposed to DWH oil and what types of injuries they suffered as a result of the DWH oil exposure, and then quantifying those injuries to determine the appropriate amount of restoration required to offset the injuries. Photographs, aerial surveys, spatial analyses of the co-occurrence between surface slick and cetacean populations, and chemical fingerprinting of oiled and stranded carcasses all confirm that at least 15 cetacean species were exposed to the DWH surface slick. Cetaceans that encountered the slick likely inhaled, aspirated, ingested, and/or adsorbed oil. In this Theme Section, marine mammal biologists, statisticians, veterinarians, toxicologists, and epidemiologists describe and quantify the adverse effects of this oil exposure. Taken together, this combination of oil spill dynamics, veterinary assessments, pathological, spatial, and temporal analyses of stranded animals, stock identification techniques, population dynamics, and a broad set of coordinated modeling efforts is an unprecedented assessment of how a major oil spill impacted a large and complex marine mammal community and their connected habitats.A simulation approach to assessing environmental risk of sound exposure to marine mammalshttp://hdl.handle.net/10023/10382
Intense underwater sounds caused by military sonar, seismic surveys, and pile driving can harm acoustically sensitive marine mammals. Many jurisdictions require such activities to undergo marine mammal impact assessments to guide mitigation. However, the ability to assess impacts in a rigorous, quantitative way is hindered by large knowledge gaps concerning hearing ability, sensitivity, and behavioral responses to noise exposure. We describe a simulation-based framework, called SAFESIMM (Statistical Algorithms For Estimating the Sonar Influence on Marine Megafauna), that can be used to calculate the numbers of agents (animals) likely to be affected by intense underwater sounds. We illustrate the simulation framework using two species that are likely to be affected by marine renewable energy developments in UK waters: gray seal (Halichoerus grypus) and harbor porpoise (Phocoena phocoena). We investigate three sources of uncertainty: How sound energy is perceived by agents with differing hearing abilities; how agents move in response to noise (i.e., the strength and directionality of their evasive movements); and the way in which these responses may interact with longer term constraints on agent movement. The estimate of received sound exposure level (SEL) is influenced most strongly by the weighting function used to account for the specie's presumed hearing ability. Strongly directional movement away from the sound source can cause modest reductions (~5 dB) in SEL over the short term (periods of less than 10 days). Beyond 10 days, the way in which agents respond to noise exposure has little or no effect on SEL, unless their movements are constrained by natural boundaries. Most experimental studies of noise impacts have been short-term. However, data are needed on long-term effects because uncertainty about predicted SELs accumulates over time. Synthesis and applications. Simulation frameworks offer a powerful way to explore, understand, and estimate effects of cumulative sound exposure on marine mammals and to quantify associated levels of uncertainty. However, they can often require subjective decisions that have important consequences for management recommendations, and the basis for these decisions must be clearly described.
Sat, 01 Apr 2017 00:00:00 GMThttp://hdl.handle.net/10023/103822017-04-01T00:00:00ZDonovan, Carl R.Harris, Catriona M.Milazzo, LorenzoHarwood, JohnMarshall, LauraWilliams, RobIntense underwater sounds caused by military sonar, seismic surveys, and pile driving can harm acoustically sensitive marine mammals. Many jurisdictions require such activities to undergo marine mammal impact assessments to guide mitigation. However, the ability to assess impacts in a rigorous, quantitative way is hindered by large knowledge gaps concerning hearing ability, sensitivity, and behavioral responses to noise exposure. We describe a simulation-based framework, called SAFESIMM (Statistical Algorithms For Estimating the Sonar Influence on Marine Megafauna), that can be used to calculate the numbers of agents (animals) likely to be affected by intense underwater sounds. We illustrate the simulation framework using two species that are likely to be affected by marine renewable energy developments in UK waters: gray seal (Halichoerus grypus) and harbor porpoise (Phocoena phocoena). We investigate three sources of uncertainty: How sound energy is perceived by agents with differing hearing abilities; how agents move in response to noise (i.e., the strength and directionality of their evasive movements); and the way in which these responses may interact with longer term constraints on agent movement. The estimate of received sound exposure level (SEL) is influenced most strongly by the weighting function used to account for the specie's presumed hearing ability. Strongly directional movement away from the sound source can cause modest reductions (~5 dB) in SEL over the short term (periods of less than 10 days). Beyond 10 days, the way in which agents respond to noise exposure has little or no effect on SEL, unless their movements are constrained by natural boundaries. Most experimental studies of noise impacts have been short-term. However, data are needed on long-term effects because uncertainty about predicted SELs accumulates over time. Synthesis and applications. Simulation frameworks offer a powerful way to explore, understand, and estimate effects of cumulative sound exposure on marine mammals and to quantify associated levels of uncertainty. However, they can often require subjective decisions that have important consequences for management recommendations, and the basis for these decisions must be clearly described.Overcoming the challenges of studying conservation physiology in large whales : a review of available methodshttp://hdl.handle.net/10023/10365
Large whales are subjected to a variety of conservation pressures that could be better monitored and managed if physiological information could be gathered readily from free-swimming whales. However, traditional approaches to studying physiology have been impractical for large whales, because there is no routine method for capture of the largest species and there is presently no practical method of obtaining blood samples from free-swimming whales. We review the currently available techniques for gathering physiological information on large whales using a variety of non-lethal and minimally invasive (or non-invasive) sample matrices. We focus on methods that should produce information relevant to conservation physiology, e.g. measures relevant to stress physiology, reproductive status, nutritional status, immune response, health, and disease. The following four types of samples are discussed: faecal samples, respiratory samples (‘blow’), skin/blubber samples, and photographs. Faecal samples have historically been used for diet analysis but increasingly are also used for hormonal analyses, as well as for assessment of exposure to toxins, pollutants, and parasites. Blow samples contain many hormones as well as respiratory microbes, a diverse array of metabolites, and a variety of immune-related substances. Biopsy dart samples are widely used for genetic, contaminant, and fatty-acid analyses and are now being used for endocrine studies along with proteomic and transcriptomic approaches. Photographic analyses have benefited from recently developed quantitative techniques allowing assessment of skin condition, ectoparasite load, and nutritional status, along with wounds and scars from ship strikes and fishing gear entanglement. Field application of these techniques has the potential to improve our understanding of the physiology of large whales greatly, better enabling assessment of the relative impacts of many anthropogenic and ecological pressures.
Wed, 15 May 2013 00:00:00 GMThttp://hdl.handle.net/10023/103652013-05-15T00:00:00ZHunt, Kathleen E.Moore, Michael J.Rolland, Rosalind M.Kellar, Nicholas M.Hall, Ailsa J.Kershaw, JoannaRaverty, Stephen A.Davis, Cristina E.Yeates, Laura C.Fauquier, Deborah A.Rowles, Teresa K.Kraus, Scott D.Large whales are subjected to a variety of conservation pressures that could be better monitored and managed if physiological information could be gathered readily from free-swimming whales. However, traditional approaches to studying physiology have been impractical for large whales, because there is no routine method for capture of the largest species and there is presently no practical method of obtaining blood samples from free-swimming whales. We review the currently available techniques for gathering physiological information on large whales using a variety of non-lethal and minimally invasive (or non-invasive) sample matrices. We focus on methods that should produce information relevant to conservation physiology, e.g. measures relevant to stress physiology, reproductive status, nutritional status, immune response, health, and disease. The following four types of samples are discussed: faecal samples, respiratory samples (‘blow’), skin/blubber samples, and photographs. Faecal samples have historically been used for diet analysis but increasingly are also used for hormonal analyses, as well as for assessment of exposure to toxins, pollutants, and parasites. Blow samples contain many hormones as well as respiratory microbes, a diverse array of metabolites, and a variety of immune-related substances. Biopsy dart samples are widely used for genetic, contaminant, and fatty-acid analyses and are now being used for endocrine studies along with proteomic and transcriptomic approaches. Photographic analyses have benefited from recently developed quantitative techniques allowing assessment of skin condition, ectoparasite load, and nutritional status, along with wounds and scars from ship strikes and fishing gear entanglement. Field application of these techniques has the potential to improve our understanding of the physiology of large whales greatly, better enabling assessment of the relative impacts of many anthropogenic and ecological pressures.From the track to the ocean : using flow control to improve marine bio-logging tags for cetaceanshttp://hdl.handle.net/10023/10300
Bio-logging tags are an important tool for the study of cetaceans, but superficial tags inevitably increase hydrodynamic loading. Substantial forces can be generated by tags on fast-swimming animals, potentially affecting behavior and energetics or promoting early tag removal. Streamlined forms have been used to reduce loading, but these designs can accelerate flow over the top of the tag. This non-axisymmetric flow results in large lift forces (normal to the animal) that become the dominant force component at high speeds. In order to reduce lift and minimize total hydrodynamic loading this work presents a new tag design (Model A) that incorporates a hydrodynamic body, a channel to reduce fluid speed differences above and below the housing and wing to redirect flow to counter lift. Additionally, three derivatives of the Model A design were used to examine the contribution of individual flow control features to overall performance. Hydrodynamic loadings of four models were compared using computational fluid dynamics (CFD). The Model A design eliminated all lift force and generated up to ~30 N of downward force in simulated 6 m/s aligned flow. The simulations were validated using particle image velocimetry (PIV) to experimentally characterize the flow around the tag design. The results of these experiments confirm the trends predicted by the simulations and demonstrate the potential benefit of flow control elements for the reduction of tag induced forces on the animal.
This project was funded by the National Oceanographic Partnership Program [National Science Foundation via the Office of Naval Research N00014-11-1-0113]. C. Spencer Garborg was supported by a Grove City College Swezey Student Fellowship to Erik Anderson. Mark Johnson was funded by a Marie Curie-Sklodowska grant from the European Union. All supplemental data files are available from the Dryad Digital Repository (doi:10.5061/dryad.4j4m1).
Tue, 14 Feb 2017 00:00:00 GMThttp://hdl.handle.net/10023/103002017-02-14T00:00:00ZFiore, GiovaniAnderson, ErikGarborg, C. SpencerMurray, MarkJohnson, MarkMoore, Michael J.Howle, LaurensShorter, K. AlexBio-logging tags are an important tool for the study of cetaceans, but superficial tags inevitably increase hydrodynamic loading. Substantial forces can be generated by tags on fast-swimming animals, potentially affecting behavior and energetics or promoting early tag removal. Streamlined forms have been used to reduce loading, but these designs can accelerate flow over the top of the tag. This non-axisymmetric flow results in large lift forces (normal to the animal) that become the dominant force component at high speeds. In order to reduce lift and minimize total hydrodynamic loading this work presents a new tag design (Model A) that incorporates a hydrodynamic body, a channel to reduce fluid speed differences above and below the housing and wing to redirect flow to counter lift. Additionally, three derivatives of the Model A design were used to examine the contribution of individual flow control features to overall performance. Hydrodynamic loadings of four models were compared using computational fluid dynamics (CFD). The Model A design eliminated all lift force and generated up to ~30 N of downward force in simulated 6 m/s aligned flow. The simulations were validated using particle image velocimetry (PIV) to experimentally characterize the flow around the tag design. The results of these experiments confirm the trends predicted by the simulations and demonstrate the potential benefit of flow control elements for the reduction of tag induced forces on the animal.Icelandic herring-eating killer whales feed at nighthttp://hdl.handle.net/10023/10208
Herring-eating killer whales debilitate herring with underwater tail slaps and likely herd herring into tighter schools using a feeding-specific low-frequency pulsed call (‘herding’ call). Feeding on herring may be dependent upon daylight, as the whales use their white underside to help herd herring; however, feeding at night has not been investigated. The production of feeding-specific sounds provides an opportunity to use passive acoustic monitoring to investigate feeding behaviour at different times of day. We compared the acoustic behaviour of killer whales between day and night, using an autonomous recorder deployed in Iceland during winter. Based upon acoustic detection of underwater tail slaps used to feed upon herring we found that killer whales fed both at night and day: they spent 50% of their time at night and 73% of daytime feeding. Interestingly, there was a significant diel variation in acoustic behaviour. Herding calls were significantly associated with underwater tail slap rate and were recorded significantly more often at night, suggesting that in low-light conditions killer whales rely more on acoustics to herd herring. Communicative sounds were also related to underwater tail slap rate and produced at different rates during day and night. The capability to adapt feeding behaviour to different light conditions may be particularly relevant for predator species occurring in high latitudes during winter, when light availability is limited.
This study was funded by an Icelandic Research Fund (i. Rannsóknasjóður, grant number 120248042) supported by a Marie Curie Fellowship.
Wed, 01 Feb 2017 00:00:00 GMThttp://hdl.handle.net/10023/102082017-02-01T00:00:00ZGaëtan, RichardFilatova, Olga AlexandrovnaSamarra, Filipa Isabel PereiraFedutin, Ivan D.Lammers, MarcMiller, PatrickHerring-eating killer whales debilitate herring with underwater tail slaps and likely herd herring into tighter schools using a feeding-specific low-frequency pulsed call (‘herding’ call). Feeding on herring may be dependent upon daylight, as the whales use their white underside to help herd herring; however, feeding at night has not been investigated. The production of feeding-specific sounds provides an opportunity to use passive acoustic monitoring to investigate feeding behaviour at different times of day. We compared the acoustic behaviour of killer whales between day and night, using an autonomous recorder deployed in Iceland during winter. Based upon acoustic detection of underwater tail slaps used to feed upon herring we found that killer whales fed both at night and day: they spent 50% of their time at night and 73% of daytime feeding. Interestingly, there was a significant diel variation in acoustic behaviour. Herding calls were significantly associated with underwater tail slap rate and were recorded significantly more often at night, suggesting that in low-light conditions killer whales rely more on acoustics to herd herring. Communicative sounds were also related to underwater tail slap rate and produced at different rates during day and night. The capability to adapt feeding behaviour to different light conditions may be particularly relevant for predator species occurring in high latitudes during winter, when light availability is limited.Whistle characteristics and daytime dive behavior in pantropical spotted dolphins (Stenella attenuata) in Hawai‘i measured using digital acoustic recording tags (DTAGs)http://hdl.handle.net/10023/10131
This study characterizes daytime acoustic and dive behavior of pantropical spotted dolphins (Stenella attenuata) in Hawai‘i using 14.58 h of data collected from five deployments of digital acoustic recording tags (DTAG3) in 2013. For each tagged animal, the number of whistles, foraging buzzes, dive profiles, and dive statistics were calculated. Start, end, minimum, and maximum frequencies, number of inflection points and duration were measured from 746 whistles. Whistles ranged in frequency from 9.7 ± 2.8 to 19.8 ± 4.2 kHz, had a mean duration of 0.7 ± 0.5 s and a mean of 1.2 ± 1.2 inflection points. Thirteen foraging buzzes were recorded across all tags. Mean dive depth and duration were 16 ± 9 m and 1.9 ± 1.0 min, respectively. Tagged animals spent the majority of time in the upper 10 m (76.9% ± 16.1%) of the water column. Both whistle frequency characteristics and dive statistics measured here were similar to previously reported values for spotted dolphins in Hawai‘i. Shallow, short dive profiles combined with few foraging buzzes provide evidence that little spotted dolphin feeding behavior occurs during daytime hours. This work represents one of the first successful DTAG3 studies of small pelagic delphinids, providing rare insights into baseline bioacoustics and dive behavior.
Funding to support P.L.T. was received from the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland) and their support is gratefully acknowledged. MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions.
Tue, 19 Jul 2016 00:00:00 GMThttp://hdl.handle.net/10023/101312016-07-19T00:00:00ZSilva, Tammy LMooney, T AranSayigh, Laela STyack, Peter LloydBaird, Robin WOswald, Julie NThis study characterizes daytime acoustic and dive behavior of pantropical spotted dolphins (Stenella attenuata) in Hawai‘i using 14.58 h of data collected from five deployments of digital acoustic recording tags (DTAG3) in 2013. For each tagged animal, the number of whistles, foraging buzzes, dive profiles, and dive statistics were calculated. Start, end, minimum, and maximum frequencies, number of inflection points and duration were measured from 746 whistles. Whistles ranged in frequency from 9.7 ± 2.8 to 19.8 ± 4.2 kHz, had a mean duration of 0.7 ± 0.5 s and a mean of 1.2 ± 1.2 inflection points. Thirteen foraging buzzes were recorded across all tags. Mean dive depth and duration were 16 ± 9 m and 1.9 ± 1.0 min, respectively. Tagged animals spent the majority of time in the upper 10 m (76.9% ± 16.1%) of the water column. Both whistle frequency characteristics and dive statistics measured here were similar to previously reported values for spotted dolphins in Hawai‘i. Shallow, short dive profiles combined with few foraging buzzes provide evidence that little spotted dolphin feeding behavior occurs during daytime hours. This work represents one of the first successful DTAG3 studies of small pelagic delphinids, providing rare insights into baseline bioacoustics and dive behavior.Phenological sensitivity to climate across taxa and trophic levelshttp://hdl.handle.net/10023/10022
Differences in phenological responses to climate change among species can desynchronise ecological interactions and thereby threaten ecosystem function. To assess these threats, we must quantify the relative impact of climate change on species at different trophic levels. Here, we apply a Climate Sensitivity Profile approach to 10,003 terrestrial and aquatic phenological data sets, spatially matched to temperature and precipitation data, to quantify variation in climate sensitivity. The direction, magnitude and timing of climate sensitivity varied markedly among organisms within taxonomic and trophic groups. Despite this variability, we detected systematic variation in the direction and magnitude of phenological climate sensitivity. Secondary consumers showed consistently lower climate sensitivity than other groups. We used mid-century climate change projections to estimate that the timing of phenological events could change more for primary consumers than for species in other trophic levels (6.2 versus 2.5–2.9 days earlier on average), with substantial taxonomic variation (1.1–14.8 days earlier on average).
This work was funded by Natural Environment Research Council (NERC) grant NE/J02080X/1. The Rothamsted Insect Survey (RIS) is a National Capability strategically funded by BBSRC.
Thu, 14 Jul 2016 00:00:00 GMThttp://hdl.handle.net/10023/100222016-07-14T00:00:00ZThackeray, Stephen J.Henrys, Peter A.Hemming, DeborahBell, James R.Botham, Marc S.Burthe, SarahHelaouet, PierreJohns, David G.Jones, Ian DLeech, David. I.Mackay, Eleanor B.Massimino, DarioAtkinson, SianBacon, Philip J.Brereton, Tom M.Carvalho, LaurenceClutton-Brock, Tim H.Duck, CallanEdwards, MartinElliott, J. MalcolmHall, Stephen J. G.Harrington, RichardPearce-Higgins, James W.Høye, Toke T.Kruuk, Loeske E. B.Pemberton, Josephine M.Sparks, Tim H.Thompson, Paul M.White, IanWinfield, Ian J.Wanless, SarahDifferences in phenological responses to climate change among species can desynchronise ecological interactions and thereby threaten ecosystem function. To assess these threats, we must quantify the relative impact of climate change on species at different trophic levels. Here, we apply a Climate Sensitivity Profile approach to 10,003 terrestrial and aquatic phenological data sets, spatially matched to temperature and precipitation data, to quantify variation in climate sensitivity. The direction, magnitude and timing of climate sensitivity varied markedly among organisms within taxonomic and trophic groups. Despite this variability, we detected systematic variation in the direction and magnitude of phenological climate sensitivity. Secondary consumers showed consistently lower climate sensitivity than other groups. We used mid-century climate change projections to estimate that the timing of phenological events could change more for primary consumers than for species in other trophic levels (6.2 versus 2.5–2.9 days earlier on average), with substantial taxonomic variation (1.1–14.8 days earlier on average).Good vibrations by the beach boys : magnitude of substrate vibrations is a reliable indicator of male grey seal sizehttp://hdl.handle.net/10023/9982
Communication via substrate vibrations can convey information on conspecific presence, individual quality, group cohesion and/or allow for predator avoidance. Although studies have identified that various species use this modality, few studies on mammalian taxa have investigated whether the information contained in substrate vibrations is a reliable indicator of resource-holding potential (RHP). The grey seal, Halichoerus grypus, breeding colony at Donna Nook, U.K., is part of a limited geographical region where the Body Slap (BS) behaviour is performed during male–male conflicts. This behaviour is thought to have a mechanical component. We examined whether the magnitude of the BS substrate vibrations contained reliable information on male mass and size as measures of RHP, and whether reliability varied across environmental conditions. To test this, we deployed seismometers during the breeding season that recorded continuous seismic data over a frequency bandwidth of 0.03–500 Hz. Locations and times of BS events performed by individual males were recorded, matched with the seismic data, and a distance-corrected magnitude was calculated for each event. Our results demonstrate the BS generates a stereotyped seismic signature measurable up to 126.3 m away. We found a positive correlation between the maximum and mean magnitudes of the substrate-borne vibrations and a male's length. Dampness of the sand substrate had no effect on magnitude. Results of this study confirm that the maximum magnitude substrate vibrations generated by the BS behaviour is an indicator of male size and that the substrate-borne vibrations are reliable across varying environmental conditions.
This work was supported by an equipment loan from the NERC SEIS UK, equipment facility (Loan no. 928) and the Durham Doctoral Studentship.
Sun, 01 Feb 2015 00:00:00 GMThttp://hdl.handle.net/10023/99822015-02-01T00:00:00ZBishop, AmandaDenton, PaulPomeroy, PatrickTwiss, SeanCommunication via substrate vibrations can convey information on conspecific presence, individual quality, group cohesion and/or allow for predator avoidance. Although studies have identified that various species use this modality, few studies on mammalian taxa have investigated whether the information contained in substrate vibrations is a reliable indicator of resource-holding potential (RHP). The grey seal, Halichoerus grypus, breeding colony at Donna Nook, U.K., is part of a limited geographical region where the Body Slap (BS) behaviour is performed during male–male conflicts. This behaviour is thought to have a mechanical component. We examined whether the magnitude of the BS substrate vibrations contained reliable information on male mass and size as measures of RHP, and whether reliability varied across environmental conditions. To test this, we deployed seismometers during the breeding season that recorded continuous seismic data over a frequency bandwidth of 0.03–500 Hz. Locations and times of BS events performed by individual males were recorded, matched with the seismic data, and a distance-corrected magnitude was calculated for each event. Our results demonstrate the BS generates a stereotyped seismic signature measurable up to 126.3 m away. We found a positive correlation between the maximum and mean magnitudes of the substrate-borne vibrations and a male's length. Dampness of the sand substrate had no effect on magnitude. Results of this study confirm that the maximum magnitude substrate vibrations generated by the BS behaviour is an indicator of male size and that the substrate-borne vibrations are reliable across varying environmental conditions.Between the devil and the deep blue sea : the role of the Amundsen Sea continental shelf in exchanges between ocean and ice shelveshttp://hdl.handle.net/10023/9976
The Amundsen Sea is a key region of Antarctica where ocean, atmosphere, sea ice and ice sheet interact. For much of Antarctica, the relatively warm ocean water in the open Southern Ocean (a few degrees above freezing) is unable to reach the continental shelf in large volumes under current climate conditions. In the Amundsen Sea, however, warm water penetrates onto the continental shelf and provides heat that can melt the underside of the floating ice shelves. Here we discuss how the role of the ocean has come under increased scrutiny in recent years, because ocean heat fluxes have been implicated in the thinning of the ice shelves. We present observations from the Amundsen Sea in 2014 and discuss their implications, highlighting aspects where our understanding is still incomplete.
This work was supported by funding from the UK Natural Environment Research Council's iSTAR Program through grants NE/J005703, NE/J005649/1 and NE/J005770/1.
Thu, 01 Dec 2016 00:00:00 GMThttp://hdl.handle.net/10023/99762016-12-01T00:00:00ZHeywood, KarenBiddle, LouiseBoehme, LarsDutrieux, PierreFedak, Michael AndreJenkins, AdrianJones, Richard W.Kaiser, JanMallett, HelenNaveira Garabato, Alberto C.Renfrew, Ian A.Stevens, David P.Webber, Benjamin G.M.The Amundsen Sea is a key region of Antarctica where ocean, atmosphere, sea ice and ice sheet interact. For much of Antarctica, the relatively warm ocean water in the open Southern Ocean (a few degrees above freezing) is unable to reach the continental shelf in large volumes under current climate conditions. In the Amundsen Sea, however, warm water penetrates onto the continental shelf and provides heat that can melt the underside of the floating ice shelves. Here we discuss how the role of the ocean has come under increased scrutiny in recent years, because ocean heat fluxes have been implicated in the thinning of the ice shelves. We present observations from the Amundsen Sea in 2014 and discuss their implications, highlighting aspects where our understanding is still incomplete.Harbour seal (Phoca vitulina) abundance within the Firth of Tay and Eden Estuary, Scotland : recent trends and extrapolation to extinctionhttp://hdl.handle.net/10023/9953
1. Aerial surveys have detected alarming declines in counts of harbour seals in several regions across Scotland. 2. Demographic data and simple models were used to examine the recent decline in the numbers of harbour seals counted in one population within a Special Area of Conservation (SAC) on the east coast of Scotland. The models suggest that the continuation of current trends would result in the species effectively disappearing from this area within the next 20 years. 3. While the cause of the decline is unknown, it must be reducing adult survival because the high rate of decline cannot be wholly accounted for by changes in other demographic parameters. 4. Recovery of the population to the abundance recorded at the time the SAC was designated (2005) is likely to take at least 40 years, even if the cause of the decline is immediately identified and removed. 5. The models suggest that partial removal of the cause can have only limited benefits to population recovery, and there are unlikely to be any long-term benefits from introducing or reintroducing additional individuals while the underlying problem persists. Therefore, if the population of harbour seals in this area is to recover it is essential that the sources of the increased mortality are identified and measures are put in place to manage these.
Aerial surveys were funded by SNH and NERC.
Fri, 17 Feb 2017 00:00:00 GMThttp://hdl.handle.net/10023/99532017-02-17T00:00:00ZHanson, NoraThompson, DaveDuck, CallanBaxter, JohnLonergan, Mike1. Aerial surveys have detected alarming declines in counts of harbour seals in several regions across Scotland. 2. Demographic data and simple models were used to examine the recent decline in the numbers of harbour seals counted in one population within a Special Area of Conservation (SAC) on the east coast of Scotland. The models suggest that the continuation of current trends would result in the species effectively disappearing from this area within the next 20 years. 3. While the cause of the decline is unknown, it must be reducing adult survival because the high rate of decline cannot be wholly accounted for by changes in other demographic parameters. 4. Recovery of the population to the abundance recorded at the time the SAC was designated (2005) is likely to take at least 40 years, even if the cause of the decline is immediately identified and removed. 5. The models suggest that partial removal of the cause can have only limited benefits to population recovery, and there are unlikely to be any long-term benefits from introducing or reintroducing additional individuals while the underlying problem persists. Therefore, if the population of harbour seals in this area is to recover it is essential that the sources of the increased mortality are identified and measures are put in place to manage these.Experimental field studies to measure behavioral responses of cetaceans to sonarhttp://hdl.handle.net/10023/9942
Substantial recent progress has been made in directly measuring behavioral responses of free-ranging marine mammals to sound using controlled exposure experiments. Many studies were motivated by concerns about observed and potential negative effects of military sonar, including stranding events. Well-established experimental methods and increasingly sophisticated technologies have enabled fine-resolution measurement of many aspects of baseline behavior and responses to sonar. Studies have considered increasingly diverse taxa, but primarily odontocete and mysticete cetaceans that are endangered, particularly sensitive, or frequently exposed to sonar. This review focuses on recent field experiments studying cetacean responses to simulated or actual active military sonars in the 1 to 8 kHz band. Overall results demonstrate that some individuals of different species display clear yet varied responses, some of which have negative implications, while others appear to tolerate relatively high levels, although such exposures may have other consequences not measured. Responses were highly variable and may not be fully predictable with simple acoustic exposure metrics (e.g. received sound level). Rather, differences among species and individuals along with contextual aspects of exposure (e.g. behavioral state) appear to affect response probability. These controlled experiments provide critically needed documentation of identified behavioral responses occurring upon known sonar exposures, and they directly inform regulatory assessments of potential effects. They also inform more targeted opportunistic monitoring of potential responses of animals during sonar operations and have stimulated adaptations of field methods to consider increasingly realistic exposure scenarios and how contextual factors such as behavioral state and source proximity influence response type and probability.
Funding was provided by a variety of military and governmental funding sources from several nations acknowledged within referenced publications, notably the US Office of Naval Research, US Navy Living Marine Resources Program, and the navies of the USA, Norway, and the Netherlands. P.L.T. acknowledges the support of the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland) in the completion of this study. MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions.
Tue, 06 Dec 2016 00:00:00 GMThttp://hdl.handle.net/10023/99422016-12-06T00:00:00ZSouthall, Brandon L.Nowacek, Douglas P.Miller, Patrick J. O.Tyack, Peter L.Substantial recent progress has been made in directly measuring behavioral responses of free-ranging marine mammals to sound using controlled exposure experiments. Many studies were motivated by concerns about observed and potential negative effects of military sonar, including stranding events. Well-established experimental methods and increasingly sophisticated technologies have enabled fine-resolution measurement of many aspects of baseline behavior and responses to sonar. Studies have considered increasingly diverse taxa, but primarily odontocete and mysticete cetaceans that are endangered, particularly sensitive, or frequently exposed to sonar. This review focuses on recent field experiments studying cetacean responses to simulated or actual active military sonars in the 1 to 8 kHz band. Overall results demonstrate that some individuals of different species display clear yet varied responses, some of which have negative implications, while others appear to tolerate relatively high levels, although such exposures may have other consequences not measured. Responses were highly variable and may not be fully predictable with simple acoustic exposure metrics (e.g. received sound level). Rather, differences among species and individuals along with contextual aspects of exposure (e.g. behavioral state) appear to affect response probability. These controlled experiments provide critically needed documentation of identified behavioral responses occurring upon known sonar exposures, and they directly inform regulatory assessments of potential effects. They also inform more targeted opportunistic monitoring of potential responses of animals during sonar operations and have stimulated adaptations of field methods to consider increasingly realistic exposure scenarios and how contextual factors such as behavioral state and source proximity influence response type and probability.Extinction is imminent for Mexico’s endemic porpoise unless fishery bycatch is eliminatedhttp://hdl.handle.net/10023/9938
The number of Mexico’s endemic porpoise, the vaquita (Phocoena sinus), is collapsing primarily due to bycatch in illegal gillnets set for totoaba (Totoaba macdonaldi), an endangered fish whose swim bladders are exported to China. Previous research estimated that vaquitas declined from about 567 to 245 individuals between 1997 and 2008. Acoustic monitoring between 2011 and 2015 showed a decline of 34%/year. Here, we combine visual line transect and passive acoustic data collected simultaneously in a robust spatial analysis to estimate that only 59 (95% Bayesian Credible Interval [CRI] 22 – 145) vaquita remained as of autumn 2015, a decrease since 1997 of 92% (95% CRI 80%-97%). Risk analysis suggests that if the current, temporary gillnet ban is maintained and effectively enforced, vaquitas could recover to 2008 population levels by 2050. Otherwise, the species is likely to be extinct within a decade.
Primary funding was by Secretaria del Medio Ambiente y Recursos Naturales (Secretario R. Pacchiano). Mexican support was from SEMARNAT, CONABIO, CONANP, PROFEPA, SEMAR, and WWF-Mexico. US support from NOAA-Fisheries-SWFSC and The Marine Mammal Center.
Thu, 12 Oct 2017 00:00:00 GMThttp://hdl.handle.net/10023/99382017-10-12T00:00:00ZTaylor, Barbara L.Rojas-Bracho, LorenzoMoore, JeffreyJaramillo-Legorreta, ArmandoVer Hoef, Jay M.Cardenas-Hinojosa, GustavoNieto-Garcia, EdwynaBarlow, JayGerrodette, TimTregenza, NicholasThomas, LenHammond, Philip S.The number of Mexico’s endemic porpoise, the vaquita (Phocoena sinus), is collapsing primarily due to bycatch in illegal gillnets set for totoaba (Totoaba macdonaldi), an endangered fish whose swim bladders are exported to China. Previous research estimated that vaquitas declined from about 567 to 245 individuals between 1997 and 2008. Acoustic monitoring between 2011 and 2015 showed a decline of 34%/year. Here, we combine visual line transect and passive acoustic data collected simultaneously in a robust spatial analysis to estimate that only 59 (95% Bayesian Credible Interval [CRI] 22 – 145) vaquita remained as of autumn 2015, a decrease since 1997 of 92% (95% CRI 80%-97%). Risk analysis suggests that if the current, temporary gillnet ban is maintained and effectively enforced, vaquitas could recover to 2008 population levels by 2050. Otherwise, the species is likely to be extinct within a decade.The challenges of analyzing behavioral response study data : an overview of the MOCHA (Multi-study OCean acoustics Human effects Analysis) projecthttp://hdl.handle.net/10023/9923
This paper describes the MOCHA project which aims to develop novel approaches for the analysis of data collected during Behavioral Response Studies (BRSs). BRSs are experiments aimed at directly quantifying the effects of controlled dosages of natural or anthropogenic stimuli (typically sound) on marine mammal behavior. These experiments typically result in low sample size, relative to variability, and so we are looking at a number of studies in combination to maximize the gain from each one. We describe a suite of analytical tools applied to BRS data on beaked whales, including a simulation study aimed at informing future experimental design.
Date of Acceptance:
Fri, 01 Jan 2016 00:00:00 GMThttp://hdl.handle.net/10023/99232016-01-01T00:00:00ZHarris, Catriona MThomas, LenSadykova, DinaraDe Ruiter, Stacy LynnTyack, Peter LloydSouthall, Brandon L.Read, Andrew J.Miller, PatrickThis paper describes the MOCHA project which aims to develop novel approaches for the analysis of data collected during Behavioral Response Studies (BRSs). BRSs are experiments aimed at directly quantifying the effects of controlled dosages of natural or anthropogenic stimuli (typically sound) on marine mammal behavior. These experiments typically result in low sample size, relative to variability, and so we are looking at a number of studies in combination to maximize the gain from each one. We describe a suite of analytical tools applied to BRS data on beaked whales, including a simulation study aimed at informing future experimental design.Sperm whale codas may encode individuality as well as clan identityhttp://hdl.handle.net/10023/9852
Sperm whales produce codas for communication that can be grouped into different types according to their temporal patterns. Codas have led researchers to propose that sperm whales belong to distinct cultural clans, but it is presently unclear if they also convey individual information. Coda clicks comprise a series of pulses and the delay between pulses is a function of organ size, and therefore body size, and so is one potential source of individual information. Another potential individual-specific parameter could be the inter-click intervals within codas. To test whether these parameters provide reliable individual cues, stereo-hydrophone acoustic tags (Dtags) were attached to five sperm whales of the Azores, recording a total of 802 codas. A discriminant function analysis was used to distinguish 288 5 Regular codas from four of the sperm whales and 183 3 Regular codas from two sperm whales. The results suggest that codas have consistent individual features in their inter-click intervals and inter-pulse intervals which may contribute to individual identification. Additionally, two whales produced different coda types in distinct foraging dive phases. Codas may therefore be used by sperm whales to convey information of identity as well as activity within a social group to a larger extent than previously assumed.
The research was funded by the Danish Research Council; the Carlsberg Foundation; Fundação para a Ciência e a Tecnologia (FCT); Fundo Regional da Ciência, Tecnologia (FRCT) through research projects TRACE-PTDC/MAR/74071/2006 and MAPCET-M2.1.2/F/012/2011 [Fundo Europeu de Desenvolvimento Regional, the Competitiveness Factors Operational (COMPETE), Quadro de Referência Estratégico Nacional (QREN) European Social Fund, and Proconvergencia Açores/European Union Program]; Aarhus University; Woods Hole Oceanographic Institution; University of Southern Denmark and University of La Laguna. We acknowledge funds provided by FCT to MARE – Marine and Environmental Sciences Centre (UID/MAR/04292/2013) and Instituto do Mar at University of the Azores and by the FRCT – Government of the Azores pluriannual funding. C.O. was funded by FCT (SFRH/BD/37668/2007). M.A.S. was supported by an FCT postdoctoral grant (SFRH/BPD/29841/2006) and is currently supported by POPH, QREN European Social Fund and the Portuguese Ministry for Science and Education, through an FCT Investigator grant. M.J. is supported by the Marine Alliance for Science and Technology Scotland (MASTS) and a Marie Curie Career Integration Grant. D.M.W. was funded by a Ph.D. stipend from the Oticon Foundation, Denmark.
Sun, 01 May 2016 00:00:00 GMThttp://hdl.handle.net/10023/98522016-05-01T00:00:00ZOliveira, CláudiaWahlberg, MagnusSilva, Mónica A.Johnson, MarkAntunes, RicardoWisniewska, Danuta M.Fais, AndreaGonçalves, JoãoMadsen, Peter T.Sperm whales produce codas for communication that can be grouped into different types according to their temporal patterns. Codas have led researchers to propose that sperm whales belong to distinct cultural clans, but it is presently unclear if they also convey individual information. Coda clicks comprise a series of pulses and the delay between pulses is a function of organ size, and therefore body size, and so is one potential source of individual information. Another potential individual-specific parameter could be the inter-click intervals within codas. To test whether these parameters provide reliable individual cues, stereo-hydrophone acoustic tags (Dtags) were attached to five sperm whales of the Azores, recording a total of 802 codas. A discriminant function analysis was used to distinguish 288 5 Regular codas from four of the sperm whales and 183 3 Regular codas from two sperm whales. The results suggest that codas have consistent individual features in their inter-click intervals and inter-pulse intervals which may contribute to individual identification. Additionally, two whales produced different coda types in distinct foraging dive phases. Codas may therefore be used by sperm whales to convey information of identity as well as activity within a social group to a larger extent than previously assumed.Adapting a computational multi agent model for humpback whale song research for use as a tool for algorithmic compositionhttp://hdl.handle.net/10023/9795
Humpback whales (Megaptera Novaengliae) present one of the most complex displays of cultural transmission amongst non-humans. During breeding seasons, male humpback whales create long, hierarchical songs, which are shared amongst a population. Every male in the population conforms to the same song in a population. During the breeding season these songs slowly change and the song at the end of the breeding season is significantly different from the song heard at the start of the breeding season. The song of a population can also be replaced, if a new song from a different population is introduced.This is known as song revolution. Our research focuses on building computational multi agent models, which seek to recreate these phenomena observed in the wild.Our research relies on methods inspired by computational multi agent models for the evolution of music. This interdisciplinary approach has allowed us to adapt our model so that it may be used not only as a scientific tool, but also a creative tool for algorithmic composition. This paper discusses the model in detail, and then demonstrates how it may be adapted for use as an algorithmic composition tool.
Wed, 31 Aug 2016 00:00:00 GMThttp://hdl.handle.net/10023/97952016-08-31T00:00:00ZMcloughlin, MichaelIngram, SimonRendell, Luke EdwardLamoni, Luca UbaldoKirke, AlexisGarland, Ellen ClareNoad, MichaelMiranda, EduardoHumpback whales (Megaptera Novaengliae) present one of the most complex displays of cultural transmission amongst non-humans. During breeding seasons, male humpback whales create long, hierarchical songs, which are shared amongst a population. Every male in the population conforms to the same song in a population. During the breeding season these songs slowly change and the song at the end of the breeding season is significantly different from the song heard at the start of the breeding season. The song of a population can also be replaced, if a new song from a different population is introduced.This is known as song revolution. Our research focuses on building computational multi agent models, which seek to recreate these phenomena observed in the wild.Our research relies on methods inspired by computational multi agent models for the evolution of music. This interdisciplinary approach has allowed us to adapt our model so that it may be used not only as a scientific tool, but also a creative tool for algorithmic composition. This paper discusses the model in detail, and then demonstrates how it may be adapted for use as an algorithmic composition tool.Biological significance of sperm whale responses to sonar: comparison with anti-predator responseshttp://hdl.handle.net/10023/9758
A key issue when investigating effects of anthropogenic noise on cetacean behavior is to identify the biological significance of the responses. Predator presence can be considered a natural high-level disturbance stimulus to which prey animals have evolved adaptive response strategies to reduce their risk of predation by altering behavior away from fitness-enhancing activities such as foraging. By contrasting the type and magnitude (duration, severity, consistency) of behavioral responses to anthropogenic noise and playback of killer whale (KW) sounds that simulated predator presence, this study aimed to provide a relative index of the disturbance level as an indication of the biological significance of responses to the anthropogenic stimulus. Using multi-sensor tags as well as visual observations of surface behavior of adult male sperm whales, we assessed a comprehensive range of behavioral metrics that could reduce individuals’ fitness if altered for a biologically relevant duration. Combining previously published results and new analyses, we showed that the responses to 1-2 kHz upsweep naval sonar and to KW playback were very similar, including horizontal avoidance, interruption of foraging or resting activities and an increase in social sound production. However, only KW playbacks elicited grouping behaviors, indicating that this social response component was specific to predator detection. Animals responded to a lesser extent to 6-7 kHz upsweep naval sonar, indicating weaker disturbance effects. Our study demonstrates the benefit of using anti-predator responses as a reference of disturbance when evaluating the relative impacts of anthropogenic stimuli, which can be of particular interest in studies of threatened species such as sperm whales.
Research funding was provided by the US Office of Naval Research and the Ministries of Defence of Norway, the Netherlands and France as well as the UK Natural Environmental Research Council.
Thu, 06 Oct 2016 00:00:00 GMThttp://hdl.handle.net/10023/97582016-10-06T00:00:00ZCuré, CharlotteIsojunno, SaanaVisser, FleurWensveen, Paul J.Sivle, Lise D.Kvadsheim, Petter H.Lam, Frans-Peter A.Miller, PatrickA key issue when investigating effects of anthropogenic noise on cetacean behavior is to identify the biological significance of the responses. Predator presence can be considered a natural high-level disturbance stimulus to which prey animals have evolved adaptive response strategies to reduce their risk of predation by altering behavior away from fitness-enhancing activities such as foraging. By contrasting the type and magnitude (duration, severity, consistency) of behavioral responses to anthropogenic noise and playback of killer whale (KW) sounds that simulated predator presence, this study aimed to provide a relative index of the disturbance level as an indication of the biological significance of responses to the anthropogenic stimulus. Using multi-sensor tags as well as visual observations of surface behavior of adult male sperm whales, we assessed a comprehensive range of behavioral metrics that could reduce individuals’ fitness if altered for a biologically relevant duration. Combining previously published results and new analyses, we showed that the responses to 1-2 kHz upsweep naval sonar and to KW playback were very similar, including horizontal avoidance, interruption of foraging or resting activities and an increase in social sound production. However, only KW playbacks elicited grouping behaviors, indicating that this social response component was specific to predator detection. Animals responded to a lesser extent to 6-7 kHz upsweep naval sonar, indicating weaker disturbance effects. Our study demonstrates the benefit of using anti-predator responses as a reference of disturbance when evaluating the relative impacts of anthropogenic stimuli, which can be of particular interest in studies of threatened species such as sperm whales.Dynamic habitat corridors for marine predators : intensive use of a coastal channel by harbour seals is modulated by tidal currentshttp://hdl.handle.net/10023/9752
Previous studies have found that predators utilise habitat corridors to ambush prey moving through them. In the marine environment, coastal channels effectively act as habitat corridors for prey movements, and sightings of predators in such areas suggest that they may target these for foraging. Unlike terrestrial systems where the underlying habitat structure is generally static, corridors in marine systems are in episodic flux due to water movements created by tidal processes. Although these hydrographic features can be highly complex, there is generally a predictable underlying cyclic tidal pattern to their structure. For marine predators that must find prey that is often patchy and widely distributed, the underlying temporal predictability in potential foraging opportunities in marine corridors may be important drivers in their use. Here we used data from land-based sightings and nineteen harbour seals (Phoca vitulina) tagged with high-resolution GPS telemetry to investigate the spatial and temporal distribution patterns of seals in a narrow tidal channel. These seals showed a striking pattern in their distribution; all seals spent a high proportion of their time around the narrowest point of the channel. There was also a distinctive tidal pattern in the use of the channel; sightings of seals in the water peaked during the flood tide and were at a minimum during the ebb tide. This pattern is likely to be related to prey availability and/or foraging efficiency driven by the underlying tidal pattern in the water movements through the channel.
The work was funded by the UK’s Natural Environment Research Council, the Department for Environment Food and Rural Affairs (RESPONSE project, NE/J004251/1 and NERC National Capability SMRU1001), Scottish Natural Heritage and Marine Scotland
Thu, 01 Dec 2016 00:00:00 GMThttp://hdl.handle.net/10023/97522016-12-01T00:00:00ZHastie, Gordon DrummondRussell, Deborah JillBenjamins, StevenMoss, SimonWilson, BenThompson, DavidPrevious studies have found that predators utilise habitat corridors to ambush prey moving through them. In the marine environment, coastal channels effectively act as habitat corridors for prey movements, and sightings of predators in such areas suggest that they may target these for foraging. Unlike terrestrial systems where the underlying habitat structure is generally static, corridors in marine systems are in episodic flux due to water movements created by tidal processes. Although these hydrographic features can be highly complex, there is generally a predictable underlying cyclic tidal pattern to their structure. For marine predators that must find prey that is often patchy and widely distributed, the underlying temporal predictability in potential foraging opportunities in marine corridors may be important drivers in their use. Here we used data from land-based sightings and nineteen harbour seals (Phoca vitulina) tagged with high-resolution GPS telemetry to investigate the spatial and temporal distribution patterns of seals in a narrow tidal channel. These seals showed a striking pattern in their distribution; all seals spent a high proportion of their time around the narrowest point of the channel. There was also a distinctive tidal pattern in the use of the channel; sightings of seals in the water peaked during the flood tide and were at a minimum during the ebb tide. This pattern is likely to be related to prey availability and/or foraging efficiency driven by the underlying tidal pattern in the water movements through the channel.Aerial low frequency hearing in captive and free-ranging harbour seals (Phoca vitulina) using auditory brainstem responseshttp://hdl.handle.net/10023/9739
The hearing sensitivity of 18 free-ranging and 10 captive harbour seals (Phoca vitulina) to aerial sounds was measured in the presence of typical environmental noise through auditory brainstem response measurements. A focus was put on the comparative hearing sensitivity at low frequencies. Low- and mid-frequency thresholds appeared to be elevated in both captive and free-ranging seals but this is likely due to masking effects and limitations of the methodology used. The data also showed individual variability in hearing sensitivity with probable age-related hearing loss found in two old harbour seals. These results suggest that the acoustic sensitivity of free-ranging animals was not negatively affected by the soundscape they experienced in the wild.
The study was funded by a grant from the UK Department of Energy and Climate Change (DECC) as part of their Offshore Energy Strategic Environmental Assessment programme.
Thu, 01 Dec 2016 00:00:00 GMThttp://hdl.handle.net/10023/97392016-12-01T00:00:00ZLucke, KlausHastie, Gordon DrummondTernes, KerstinMcConnell, Bernie JMoss, SimonRussell, Deborah JillWeber, HeikeJanik, Vincent M.The hearing sensitivity of 18 free-ranging and 10 captive harbour seals (Phoca vitulina) to aerial sounds was measured in the presence of typical environmental noise through auditory brainstem response measurements. A focus was put on the comparative hearing sensitivity at low frequencies. Low- and mid-frequency thresholds appeared to be elevated in both captive and free-ranging seals but this is likely due to masking effects and limitations of the methodology used. The data also showed individual variability in hearing sensitivity with probable age-related hearing loss found in two old harbour seals. These results suggest that the acoustic sensitivity of free-ranging animals was not negatively affected by the soundscape they experienced in the wild.Predicting the effects of human developments on individual dolphins to understand potential long-term population consequenceshttp://hdl.handle.net/10023/9731
Human activities that impact wildlife do not necessarily remove individuals from populations. They may also change individual behaviour in ways that have sublethal effects. This has driven interest in developing analytical tools that predict the population consequences of short-term behavioural responses. In this study, we incorporate empirical information on the ecology of a population of bottlenose dolphins into an individual-based model that predicts how individuals' behavioural dynamics arise from their underlying motivational states, as well as their interaction with boat traffic and dredging activities. We simulate the potential effects of proposed coastal developments on this population and predict that the operational phase may affect animals' motivational states. For such results to be relevant for management, the effects on individuals' vital rates also need to be quantified. We investigate whether the relationship between an individual's exposure and the survival of its calves can be directly estimated using a Bayesian multi-stage model for calf survival. The results suggest that any effect on calf survival is probably small and that a significant relationship could only be detected in large, closely studied populations. Our work can be used to guide management decisions, accelerate the consenting process for coastal and offshore developments and design targeted monitoring
This work received funding from the Marine Alliance for Science and Technology for Scotland (MASTS pooling initiative).
Sun, 01 Nov 2015 00:00:00 GMThttp://hdl.handle.net/10023/97312015-11-01T00:00:00ZPirotta, EnricoHarwood, JohnThompson, PaulNew, LeslieCheney, BarbaraArso Civil, MonicaHammond, Philip StevenDonovan, Carl RobertLusseau, DavidHuman activities that impact wildlife do not necessarily remove individuals from populations. They may also change individual behaviour in ways that have sublethal effects. This has driven interest in developing analytical tools that predict the population consequences of short-term behavioural responses. In this study, we incorporate empirical information on the ecology of a population of bottlenose dolphins into an individual-based model that predicts how individuals' behavioural dynamics arise from their underlying motivational states, as well as their interaction with boat traffic and dredging activities. We simulate the potential effects of proposed coastal developments on this population and predict that the operational phase may affect animals' motivational states. For such results to be relevant for management, the effects on individuals' vital rates also need to be quantified. We investigate whether the relationship between an individual's exposure and the survival of its calves can be directly estimated using a Bayesian multi-stage model for calf survival. The results suggest that any effect on calf survival is probably small and that a significant relationship could only be detected in large, closely studied populations. Our work can be used to guide management decisions, accelerate the consenting process for coastal and offshore developments and design targeted monitoringNavigating uncertain waters: a critical review of inferring foraging behaviour from location and dive data in pinnipedshttp://hdl.handle.net/10023/9705
In the last thirty years, the emergence and progression of biologging technology has led to great advances in marine predator ecology. Large databases of location and dive observations from biologging devices have been compiled for an increasing number of diving predator species (such as pinnipeds, sea turtles, seabirds and cetaceans), enabling complex questions about animal activity budgets and habitat use to be addressed. Central to answering these questions is our ability to correctly identify and quantify the frequency of essential behaviours, such as foraging. Despite technological advances that have increased the quality and resolution of location and dive data, accurately interpreting behaviour from such data remains a challenge, and analytical methods are only beginning to unlock the full potential of existing datasets. This review evaluates both traditional and emerging methods and presents a starting platform of options for future studies of marine predator foraging ecology, particularly from location and two-dimensional (time-depth) dive data. We outline the different devices and data types available, discuss the limitations and advantages of commonly-used analytical techniques, and highlight key areas for future research. We focus our review on pinnipeds - one of the most studied taxa of marine predators - but offer insights that will be applicable to other air-breathing marine predator tracking studies. We highlight that traditionally-used methods for inferring foraging from location and dive data, such as first-passage time and dive shape analysis, have important caveats and limitations depending on the nature of the data and the research question. We suggest that more holistic statistical techniques, such as state-space models, which can synthesise multiple track, dive and environmental metrics whilst simultaneously accounting for measurement error, offer more robust alternatives. Finally, we identify a need for more research to elucidate the role of physical oceanography, device effects, study animal selection, and developmental stages in predator behaviour and data interpretation.
MIDC PhD studentship co-funded by Natural Environmental Research Council (NERC) and School of Marine Science and Engineering, Plymouth University. DJFR is supported by National Capability funding from NERC to the Sea Mammal Research Unit (grant no. SMRU1001).
Wed, 26 Oct 2016 00:00:00 GMThttp://hdl.handle.net/10023/97052016-10-26T00:00:00ZCarter, Matt Ian DanielBennett, Kimberley A.Embling, Clare B.Hosegood, Philip J.Russell, Debbie J. F.In the last thirty years, the emergence and progression of biologging technology has led to great advances in marine predator ecology. Large databases of location and dive observations from biologging devices have been compiled for an increasing number of diving predator species (such as pinnipeds, sea turtles, seabirds and cetaceans), enabling complex questions about animal activity budgets and habitat use to be addressed. Central to answering these questions is our ability to correctly identify and quantify the frequency of essential behaviours, such as foraging. Despite technological advances that have increased the quality and resolution of location and dive data, accurately interpreting behaviour from such data remains a challenge, and analytical methods are only beginning to unlock the full potential of existing datasets. This review evaluates both traditional and emerging methods and presents a starting platform of options for future studies of marine predator foraging ecology, particularly from location and two-dimensional (time-depth) dive data. We outline the different devices and data types available, discuss the limitations and advantages of commonly-used analytical techniques, and highlight key areas for future research. We focus our review on pinnipeds - one of the most studied taxa of marine predators - but offer insights that will be applicable to other air-breathing marine predator tracking studies. We highlight that traditionally-used methods for inferring foraging from location and dive data, such as first-passage time and dive shape analysis, have important caveats and limitations depending on the nature of the data and the research question. We suggest that more holistic statistical techniques, such as state-space models, which can synthesise multiple track, dive and environmental metrics whilst simultaneously accounting for measurement error, offer more robust alternatives. Finally, we identify a need for more research to elucidate the role of physical oceanography, device effects, study animal selection, and developmental stages in predator behaviour and data interpretation.Population scaling in 5 km x 5 km grey and harbour seal usage maps. Note to Scottish Government MMSS/002/15http://hdl.handle.net/10023/9704
Fri, 14 Oct 2016 00:00:00 GMThttp://hdl.handle.net/10023/97042016-10-14T00:00:00ZJones, Esther LaneMorris, ChristopherSmout, Sophie CarolineMcConnell, Bernie JCultural turnover among Galápagos sperm whaleshttp://hdl.handle.net/10023/9699
While populations may wax and wane, it is rare for an entire population to be replaced by a completely different set of individuals. We document the large-scale relocation of cultural groups of sperm whale off the Galápagos Islands, in which two sympatric vocal clans were entirely replaced by two different ones. Between 1985 and 1999, whales from two clans (called Regular and Plus-One) defined by cultural dialects in coda vocalizations were repeatedly photo-identified off Galápagos. Their occurrence in the area declined through the 1990s; by 2000, none remained. We reassessed Galápagos sperm whales in 2013–2014, identifying 463 new females. However, re-sighting rates were low, with no matches with the Galápagos 1985–1999 population, suggesting an eastward shift to coastal areas. Their vocal repertoires matched those of two other clans (called Short and Four-Plus) found across the Pacific but previously rare or absent around Galápagos. The mechanisms behind this cultural turnover may include large-scale environmental regime shifts favouring clan-specific foraging strategies, and a response to heavy whaling in the region involving redistribution of surviving whales into high-quality habitats. The fall and rise of sperm whale cultures off Galápagos reflect the structuring of the Pacific population into large, enduring clans with dynamic ranges. Long-lasting clan membership illustrates how culture can be bound up in the structure and dynamics of animal populations and so how tracking cultural traits can reveal large-scale population shifts.
Funding: Marine Alliance for Science and Technology for Scotland pooling initiative, which is funded by the Scottish Funding Council (#HR09011) and contributing institutions.
Sat, 01 Oct 2016 00:00:00 GMThttp://hdl.handle.net/10023/96992016-10-01T00:00:00ZCantor, MauricioWhitehead, HalGero, ShaneRendell, Luke EdwardWhile populations may wax and wane, it is rare for an entire population to be replaced by a completely different set of individuals. We document the large-scale relocation of cultural groups of sperm whale off the Galápagos Islands, in which two sympatric vocal clans were entirely replaced by two different ones. Between 1985 and 1999, whales from two clans (called Regular and Plus-One) defined by cultural dialects in coda vocalizations were repeatedly photo-identified off Galápagos. Their occurrence in the area declined through the 1990s; by 2000, none remained. We reassessed Galápagos sperm whales in 2013–2014, identifying 463 new females. However, re-sighting rates were low, with no matches with the Galápagos 1985–1999 population, suggesting an eastward shift to coastal areas. Their vocal repertoires matched those of two other clans (called Short and Four-Plus) found across the Pacific but previously rare or absent around Galápagos. The mechanisms behind this cultural turnover may include large-scale environmental regime shifts favouring clan-specific foraging strategies, and a response to heavy whaling in the region involving redistribution of surviving whales into high-quality habitats. The fall and rise of sperm whale cultures off Galápagos reflect the structuring of the Pacific population into large, enduring clans with dynamic ranges. Long-lasting clan membership illustrates how culture can be bound up in the structure and dynamics of animal populations and so how tracking cultural traits can reveal large-scale population shifts.Individual size, sex and rearing environment impact on aggression in newly weaned sealshttp://hdl.handle.net/10023/9690
Sat, 01 Apr 2017 00:00:00 GMThttp://hdl.handle.net/10023/96902017-04-01T00:00:00ZRobinson, Kelly J.Pomeroy, Patrick P.Hazon, NeilMoss, SimonTwiss, Sean D.Whale, whale, everywhere: increasing abundance of western South Atlantic humpback whales (Megaptera novaeangliae) in their wintering groundshttp://hdl.handle.net/10023/9662
The western South Atlantic (WSA) humpback whale population inhabits the coast of Brazil during the breeding and calving season in winter and spring. This population was depleted to near extinction by whaling in the mid-twentieth century. Despite recent signs of recovery, increasing coastal and offshore development pose potential threats to these animals. Therefore, continuous monitoring is needed to assess population status and support conservation strategies. The aim of this work was to present ship-based line-transect estimates of abundance for humpback whales in their WSA breeding ground and to investigate potential changes in population size. Two cruises surveyed the coast of Brazil during August-September in 2008 and 2012. The area surveyed in 2008 corresponded to the currently recognized population breeding area; effort in 2012 was limited due to unfavorable weather conditions. WSA humpback whale population size in 2008 was estimated at 16,410 (CV = 0.228, 95% CI = 10,563–25,495) animals. In order to compare abundance between 2008 and 2012, estimates for the area between Salvador and Cabo Frio, which were consistently covered in the two years, were computed at 15,332 (CV = 0.243, 95% CI = 9,595–24,500) and 19,429 (CV = 0.101, 95% CI = 15,958–23,654) whales, respectively. The difference in the two estimates represents an increase of 26.7% in whale numbers in a 4-year period. The estimated abundance for 2008 is considered the most robust for the WSA humpback whale population because the ship survey conducted in that year minimized bias from various sources. Results presented here indicate that in 2008, the WSA humpback whale population was at least around 60% of its estimated pre-modern whaling abundance and that it may recover to its pre-exploitation size sooner than previously estimated.
Thu, 13 Oct 2016 00:00:00 GMThttp://hdl.handle.net/10023/96622016-10-13T00:00:00ZBortolotto, Guilherme A.Danilewicz, DanielAndriolo, ArturSecchi, Eduardo R.Zerbini, Alexandre N.The western South Atlantic (WSA) humpback whale population inhabits the coast of Brazil during the breeding and calving season in winter and spring. This population was depleted to near extinction by whaling in the mid-twentieth century. Despite recent signs of recovery, increasing coastal and offshore development pose potential threats to these animals. Therefore, continuous monitoring is needed to assess population status and support conservation strategies. The aim of this work was to present ship-based line-transect estimates of abundance for humpback whales in their WSA breeding ground and to investigate potential changes in population size. Two cruises surveyed the coast of Brazil during August-September in 2008 and 2012. The area surveyed in 2008 corresponded to the currently recognized population breeding area; effort in 2012 was limited due to unfavorable weather conditions. WSA humpback whale population size in 2008 was estimated at 16,410 (CV = 0.228, 95% CI = 10,563–25,495) animals. In order to compare abundance between 2008 and 2012, estimates for the area between Salvador and Cabo Frio, which were consistently covered in the two years, were computed at 15,332 (CV = 0.243, 95% CI = 9,595–24,500) and 19,429 (CV = 0.101, 95% CI = 15,958–23,654) whales, respectively. The difference in the two estimates represents an increase of 26.7% in whale numbers in a 4-year period. The estimated abundance for 2008 is considered the most robust for the WSA humpback whale population because the ship survey conducted in that year minimized bias from various sources. Results presented here indicate that in 2008, the WSA humpback whale population was at least around 60% of its estimated pre-modern whaling abundance and that it may recover to its pre-exploitation size sooner than previously estimated.Addressing uncertainty in marine resource management; combining community engagement and tracking technology to characterize human behaviorhttp://hdl.handle.net/10023/9433
Small-scale fisheries provide an essential source of food and employment for coastal communities, yet the availability of detailed information on the spatiotemporal distribution of fishing effort to support resource management at a country level is scarce. Here, using a national-scale study in the Republic of Congo, we engaged with fishers from 23 of 28 small-scale fisheries landing sites along the coast to demonstrate how combining community engagement and relatively low cost Global Positioning System (GPS) trackers can rapidly provide fine-scale information on: (1) the behavioral dynamics of the fishers and fleets that operate within this sector; and (2) the location, size and attributes of important fishing grounds upon which communities are dependent. This multi-disciplinary approach should be considered within a global context where uncertainty over the behavior of marine and terrestrial resource-users can lead to management decisions that potentially compromise local livelihoods, conservation, and resource sustainability goals.
This study was approved by the University of Exeter Ethics committee and the Ministry of Scientific Research and Technological Innovation in Congo (Permit: No. 023/MRSIT/DGRST/DMAST); and supported by funding from the Darwin Initiative (Projects 20-009 and 23-011) and the Wildlife Conservation Society.
Mon, 14 Aug 2017 00:00:00 GMThttp://hdl.handle.net/10023/94332017-08-14T00:00:00ZMetcalfe, KristianCollins, TimAbernethy, Kirsten E.Boumba, RichardDengui, Jean-ClaudeMiyalou, RickyParnell, Richard J.Plummer, Kate E.Russell, Debbie J. F.Safou, Gilbert KoumbaTilley, DominicTurner, Rachel A.VanLeeuwe, HildeWitt, Matthew J.Godley, Brendan J.Small-scale fisheries provide an essential source of food and employment for coastal communities, yet the availability of detailed information on the spatiotemporal distribution of fishing effort to support resource management at a country level is scarce. Here, using a national-scale study in the Republic of Congo, we engaged with fishers from 23 of 28 small-scale fisheries landing sites along the coast to demonstrate how combining community engagement and relatively low cost Global Positioning System (GPS) trackers can rapidly provide fine-scale information on: (1) the behavioral dynamics of the fishers and fleets that operate within this sector; and (2) the location, size and attributes of important fishing grounds upon which communities are dependent. This multi-disciplinary approach should be considered within a global context where uncertainty over the behavior of marine and terrestrial resource-users can lead to management decisions that potentially compromise local livelihoods, conservation, and resource sustainability goals.Patterns of space use in sympatric marine colonial predators reveals scales of spatial partitioninghttp://hdl.handle.net/10023/9386
Species distribution maps can provide important information to focus conservation efforts and enable spatial management of human activities. Two sympatric marine predators, grey seals Halichoerus grypus and harbour seals Phoca vitulina have overlapping ranges on land and at sea but contrasting population dynamics around Britain: whilst grey seals have generally increased, harbour seals have shown significant regional declines. We analysed two decades of at-sea movement data and terrestrial count data from these species to produce high resolution, broad-scale maps of distribution and associated uncertainty to inform conservation and management. Our results showed that grey seals use offshore areas connected to their haul-out sites by prominent corridors and harbour seals primarily stay within 50km of the coastline. Both species show fine-scale offshore spatial segregation off the east coast of Britain and broad-scale partitioning off western Scotland. These results illustrate that for broad-scale marine spatial planning, the conservation needs of harbour seals (primarily inshore, the exception being selected offshore usage areas) are different from those of grey seals (up to 100km offshore and corridors connecting these areas to haul-out sites). More generally, our results illustrate the importance of detailed knowledge of marine predator distributions to inform marine spatial planning; for instance, spatial prioritisation is not necessarily the most effective spatial planning strategy even when conserving species with similar taxonomy.
E.L.J. and D.J.F.R. were funded under Scottish Government grant MMSS001/01. D.J.F.R. was funded by the UK Department of Energy and Climate Change (DECC) as part of their Offshore Energy Strategic Environmental Assessment programme. S.S. was part-funded by the EU MYFISH project.
Thu, 27 Aug 2015 00:00:00 GMThttp://hdl.handle.net/10023/93862015-08-27T00:00:00ZJones, Esther LaneMcConnell, Bernie JSmout, Sophie CarolineHammond, Philip StevenDuck, Callan DavidMorris, ChristopherThompson, DavidRussell, Deborah Jill FraserVincent, CecileCronin, MichelleSharples, Ruth JemmaMatthiopoulos, JasonSpecies distribution maps can provide important information to focus conservation efforts and enable spatial management of human activities. Two sympatric marine predators, grey seals Halichoerus grypus and harbour seals Phoca vitulina have overlapping ranges on land and at sea but contrasting population dynamics around Britain: whilst grey seals have generally increased, harbour seals have shown significant regional declines. We analysed two decades of at-sea movement data and terrestrial count data from these species to produce high resolution, broad-scale maps of distribution and associated uncertainty to inform conservation and management. Our results showed that grey seals use offshore areas connected to their haul-out sites by prominent corridors and harbour seals primarily stay within 50km of the coastline. Both species show fine-scale offshore spatial segregation off the east coast of Britain and broad-scale partitioning off western Scotland. These results illustrate that for broad-scale marine spatial planning, the conservation needs of harbour seals (primarily inshore, the exception being selected offshore usage areas) are different from those of grey seals (up to 100km offshore and corridors connecting these areas to haul-out sites). More generally, our results illustrate the importance of detailed knowledge of marine predator distributions to inform marine spatial planning; for instance, spatial prioritisation is not necessarily the most effective spatial planning strategy even when conserving species with similar taxonomy.Body density and diving gas volume of the northern bottlenose whale (Hyperoodon ampullatus)http://hdl.handle.net/10023/9326
Diving lung volume and tissue density, reflecting lipid store volume, are important physiological parameters that have only been estimated for a few breath-hold diving species. We fitted 12 northern bottlenose whales with data loggers that recorded depth, 3-axis acceleration and speed either with a fly-wheel or from change of depth corrected by pitch angle.We fitted measured values of the change in speed during 5 s descent and ascent glides to a hydrodynamic model of drag and buoyancy forces using a Bayesian estimation framework. The resulting estimate of diving gas volume was 27.4±4.2 (95% credible interval, CI) ml kg−1, closely matching the measured lung capacity of the species. Dive-by-dive variation in gas volume did not correlate with dive depth or duration. Estimated body densities of individuals ranged from 1028.4 to 1033.9 kg m−3 at the sea surface, indicating overall negative tissue buoyancy of this species in seawater. Body density estimates were highly precise with ±95% CI ranging from 0.1to 0.4 kg m−3, which would equate to a precision of <0.5% of lipid content based upon extrapolation from the elephant seal. Six whales tagged near Jan Mayen (Norway, 71°N) had lower body density and were closer to neutral buoyancy than six whales tagged in the Gully (Nova Scotia, Canada, 44°N), a difference that was consistent with the amount of gliding observed during ascent versus descent phases in these animals. Implementation of this approach using longer duration tags could be used to track longitudinal changes in body density and lipid store body condition of free-ranging cetaceans.
Funding for fieldwork and data analysis was provided by the Strategic Environmental Research and Development Program (SERDP), project RC-2337
Wed, 17 Aug 2016 00:00:00 GMThttp://hdl.handle.net/10023/93262016-08-17T00:00:00ZMiller, PatrickNarazaki, TomokoIsojunno, SaanaSuzuki, KagariSmout, Sophie CarolineSato, KatsufumiDiving lung volume and tissue density, reflecting lipid store volume, are important physiological parameters that have only been estimated for a few breath-hold diving species. We fitted 12 northern bottlenose whales with data loggers that recorded depth, 3-axis acceleration and speed either with a fly-wheel or from change of depth corrected by pitch angle.We fitted measured values of the change in speed during 5 s descent and ascent glides to a hydrodynamic model of drag and buoyancy forces using a Bayesian estimation framework. The resulting estimate of diving gas volume was 27.4±4.2 (95% credible interval, CI) ml kg−1, closely matching the measured lung capacity of the species. Dive-by-dive variation in gas volume did not correlate with dive depth or duration. Estimated body densities of individuals ranged from 1028.4 to 1033.9 kg m−3 at the sea surface, indicating overall negative tissue buoyancy of this species in seawater. Body density estimates were highly precise with ±95% CI ranging from 0.1to 0.4 kg m−3, which would equate to a precision of <0.5% of lipid content based upon extrapolation from the elephant seal. Six whales tagged near Jan Mayen (Norway, 71°N) had lower body density and were closer to neutral buoyancy than six whales tagged in the Gully (Nova Scotia, Canada, 44°N), a difference that was consistent with the amount of gliding observed during ascent versus descent phases in these animals. Implementation of this approach using longer duration tags could be used to track longitudinal changes in body density and lipid store body condition of free-ranging cetaceans.Quantifying similarity in animal vocal sequences : which metric performs best?http://hdl.handle.net/10023/9266
1. Many animals communicate using sequences of discrete acoustic elements which can be complex, vary in their degree of stereotypy, and are potentially open-ended. Variation in sequences can provide important ecological, behavioural, or evolutionary information about the structure and connectivity of populations, mechanisms for vocal cultural evolution, and the underlying drivers responsible for these processes. Various mathematical techniques have been used to form a realistic approximation of sequence similarity for such tasks. 2. Here, we use both simulated and empirical datasets from animal vocal sequences (rock hyrax, Procavia capensis; humpback whale, Megaptera novaeangliae; bottlenose dolphin, Tursiops truncatus; and Carolina chickadee, Poecile carolinensis) to test which of eight sequence analysis metrics are more likely to reconstruct the information encoded in the sequences, and to test the fidelity of estimation of model parameters, when the sequences are assumed to conform to particular statistical models. 3. Results from the simulated data indicated that multiple metrics were equally successful in reconstructing the information encoded in the sequences of simulated individuals (Markov chains, n-gram models, repeat distribution, and edit distance), and data generated by different stochastic processes (entropy rate and n-grams). However, the string edit (Levenshtein) distance performed consistently and significantly better than all other tested metrics (including entropy, Markov chains, n-grams, mutual information) for all empirical datasets, despite being less commonly used in the field of animal acoustic communication. 4. The Levenshtein distance metric provides a robust analytical approach that should be considered in the comparison of animal acoustic sequences in preference to other commonly employed techniques (such as Markov chains, hidden Markov models, or Shannon entropy). The recent discovery that non-Markovian vocal sequences may be more common in animal communication than previously thought, provides a rich area for future research that requires non-Markovian based analysis techniques to investigate animal grammars and potentially the origin of human language.
E.C.G is supported by a Newton International Fellowship. Part of this work was conducted while E.C.G. was supported by a National Research Council (National Academy of Sciences) Postdoctoral Fellowship at the National Marine Mammal Laboratory, AFSC, NMFS, NOAA.
Tue, 01 Dec 2015 00:00:00 GMThttp://hdl.handle.net/10023/92662015-12-01T00:00:00ZKershenbaum, ArikGarland, Ellen Clare1. Many animals communicate using sequences of discrete acoustic elements which can be complex, vary in their degree of stereotypy, and are potentially open-ended. Variation in sequences can provide important ecological, behavioural, or evolutionary information about the structure and connectivity of populations, mechanisms for vocal cultural evolution, and the underlying drivers responsible for these processes. Various mathematical techniques have been used to form a realistic approximation of sequence similarity for such tasks. 2. Here, we use both simulated and empirical datasets from animal vocal sequences (rock hyrax, Procavia capensis; humpback whale, Megaptera novaeangliae; bottlenose dolphin, Tursiops truncatus; and Carolina chickadee, Poecile carolinensis) to test which of eight sequence analysis metrics are more likely to reconstruct the information encoded in the sequences, and to test the fidelity of estimation of model parameters, when the sequences are assumed to conform to particular statistical models. 3. Results from the simulated data indicated that multiple metrics were equally successful in reconstructing the information encoded in the sequences of simulated individuals (Markov chains, n-gram models, repeat distribution, and edit distance), and data generated by different stochastic processes (entropy rate and n-grams). However, the string edit (Levenshtein) distance performed consistently and significantly better than all other tested metrics (including entropy, Markov chains, n-grams, mutual information) for all empirical datasets, despite being less commonly used in the field of animal acoustic communication. 4. The Levenshtein distance metric provides a robust analytical approach that should be considered in the comparison of animal acoustic sequences in preference to other commonly employed techniques (such as Markov chains, hidden Markov models, or Shannon entropy). The recent discovery that non-Markovian vocal sequences may be more common in animal communication than previously thought, provides a rich area for future research that requires non-Markovian based analysis techniques to investigate animal grammars and potentially the origin of human language.The difference between night and day : the nocturnal and diurnal activity budget of gray seals (Halichoerus grypus) during the breeding seasonhttp://hdl.handle.net/10023/9265
Fri, 01 Jan 2016 00:00:00 GMThttp://hdl.handle.net/10023/92652016-01-01T00:00:00ZCulloch, R.M.Pomeroy, P.P.Twiss, S.D.Salmonella infection in grey seals (Halichoerus grypus), a marine mammal sentinel species : pathogenicity and molecular typing of Salmonella strains compared with human and livestock isolateshttp://hdl.handle.net/10023/9252
Microbial pollution of the marine environment through land-sea transfer of human and livestock pathogens is of concern. Salmonella was isolated from rectal swabs of free-ranging and stranded grey seal pups (21.1%; 37/175) and compared to strains from the same serovars isolated from human clinical cases, livestock, wild mammals and birds in Scotland, UK to characterise possible transmission routes using pulsed-field gel electrophoresis (PFGE) and multi-locus variable number of tandem repeat (MLVA) analyses. A higher prevalence of Salmonella was found in pups exposed to sea-water, suggesting that this may represent a source of this pathogen. Salmonella Bovismorbificans was the most common isolate (18.3% pups; 32/175) and was indistinguishable from isolates found in Scottish cattle. Salmonella Typhimurium was infrequent (2.3% pups; 4/175), mostly similar to isolates found in garden birds and, in one case, identical to a highly multidrug resistant strain isolated from a human child. Salmonella Haifa was rare (1.1% pups; 2/175) but isolates were indistinguishable from that of a human clinical isolate. These results suggest that S. Bovismorbificans may circulate between grey seal and cattle populations and that both S. Typhimurium and S. Haifa isolates are shared with humans, raising concerns of microbial marine pollution.
This work and JLB’s PhD studentship were funded by the Moredun Research Institute and the Royal Zoological Society of Scotland.
Tue, 15 Mar 2016 00:00:00 GMThttp://hdl.handle.net/10023/92522016-03-15T00:00:00ZBaily, Johanna LFoster, GeoffreyBrown, DerekDavison, NickCoia, John EWatson, EleanorPizzi, RomainWilloughby, KimHall, Ailsa JDagleish, Mark PMicrobial pollution of the marine environment through land-sea transfer of human and livestock pathogens is of concern. Salmonella was isolated from rectal swabs of free-ranging and stranded grey seal pups (21.1%; 37/175) and compared to strains from the same serovars isolated from human clinical cases, livestock, wild mammals and birds in Scotland, UK to characterise possible transmission routes using pulsed-field gel electrophoresis (PFGE) and multi-locus variable number of tandem repeat (MLVA) analyses. A higher prevalence of Salmonella was found in pups exposed to sea-water, suggesting that this may represent a source of this pathogen. Salmonella Bovismorbificans was the most common isolate (18.3% pups; 32/175) and was indistinguishable from isolates found in Scottish cattle. Salmonella Typhimurium was infrequent (2.3% pups; 4/175), mostly similar to isolates found in garden birds and, in one case, identical to a highly multidrug resistant strain isolated from a human child. Salmonella Haifa was rare (1.1% pups; 2/175) but isolates were indistinguishable from that of a human clinical isolate. These results suggest that S. Bovismorbificans may circulate between grey seal and cattle populations and that both S. Typhimurium and S. Haifa isolates are shared with humans, raising concerns of microbial marine pollution.Variability in individual rates of aggression in wild gray seals : fine-scale analysis reveals importance of social and spatial stabilityhttp://hdl.handle.net/10023/9229
Aggressive interactions are costly for individuals in time, energy, or physical damage, and in polygynous mating systems, there is high variability in the rates and intensity of aggression across individuals and within breeding seasons. However, examinations into the drivers of this variability are often conducted in isolation, in non-wild systems, or the predictor variables in question, for example, dominance, are averaged across large spatial, social, or temporal scales. The aim of this study was to adopt a fine spatial and temporal scale approach to investigate the factors associated with inter-individual variation in aggression in wild, breeding male gray seals within three consecutive breeding seasons. To do this, we fit models examining if the daily frequency of aggression and probability of escalated aggression for males was best explained by factors such as dominance score, proximity to competitors or females, local social stability, and the occurrence of stochastic environmental events. Stability of neighbor identities was the strongest correlate of reduced male aggression. Dominance status did not correlate with aggression at the daily scale, with the exception of one period after a natural disturbance to the breeding colony where dominant males had relatively reduced rates of aggression. These findings emphasize the importance of local social stability in explaining inter-individual variation in aggression in a wild population and suggest that factors associated with aggression are context dependent in relation to the natural environment. Furthermore, we highlight the utility of a fine temporal scale and incorporating spatial parameters when investigating variability in aggression in wild systems.
This study was funded by a Durham Doctoral Studentship awarded to author AB.
Thu, 01 Oct 2015 00:00:00 GMThttp://hdl.handle.net/10023/92292015-10-01T00:00:00ZBishop, A.M.Pomeroy, P.Twiss, S.D.Aggressive interactions are costly for individuals in time, energy, or physical damage, and in polygynous mating systems, there is high variability in the rates and intensity of aggression across individuals and within breeding seasons. However, examinations into the drivers of this variability are often conducted in isolation, in non-wild systems, or the predictor variables in question, for example, dominance, are averaged across large spatial, social, or temporal scales. The aim of this study was to adopt a fine spatial and temporal scale approach to investigate the factors associated with inter-individual variation in aggression in wild, breeding male gray seals within three consecutive breeding seasons. To do this, we fit models examining if the daily frequency of aggression and probability of escalated aggression for males was best explained by factors such as dominance score, proximity to competitors or females, local social stability, and the occurrence of stochastic environmental events. Stability of neighbor identities was the strongest correlate of reduced male aggression. Dominance status did not correlate with aggression at the daily scale, with the exception of one period after a natural disturbance to the breeding colony where dominant males had relatively reduced rates of aggression. These findings emphasize the importance of local social stability in explaining inter-individual variation in aggression in a wild population and suggest that factors associated with aggression are context dependent in relation to the natural environment. Furthermore, we highlight the utility of a fine temporal scale and incorporating spatial parameters when investigating variability in aggression in wild systems.Sperm whale predator-prey interactions involve chasing and buzzing, but no acoustic stunninghttp://hdl.handle.net/10023/9156
The sperm whale carries a hypertrophied nose that generates powerful clicks for long-range echolocation. However, it remains a conundrum how this bizarrely shaped apex predator catches its prey. Several hypotheses have been advanced to propose both active and passive means to acquire prey, including acoustic debilitation of prey with very powerful clicks. Here we test these hypotheses by using sound and movement recording tags in a fine-scale study of buzz sequences to relate the acoustic behaviour of sperm whales with changes in acceleration in their head region during prey capture attempts. We show that in the terminal buzz phase, sperm whales reduce inter-click intervals and estimated source levels by 1-2 orders of magnitude. As a result, received levels at the prey are more than an order of magnitude below levels required for debilitation, precluding acoustic stunning to facilitate prey capture. Rather, buzzing involves high-frequency, low amplitude clicks well suited to provide high-resolution biosonar updates during the last stages of capture. The high temporal resolution helps to guide motor patterns during occasionally prolonged chases in which prey are eventually subdued with the aid of fast jaw movements and/or buccal suction as indicated by acceleration transients (jerks) near the end of buzzes.
Field work in Norway was funded by the Carlsberg Foundation and the National Danish Research Council to PTM. The NMFS study was funded by the U.S. Mineral Management Service. MJ is funded by the Marine Alliance for Science and Technology, Scotland, and by a Marie Curie Career Integration Grant. MW was funded by the Danish Council for Independent Research, Natural Science and NAS is currently funded by a EU Horizon 2020 MSC Fellowship.
Fri, 24 Jun 2016 00:00:00 GMThttp://hdl.handle.net/10023/91562016-06-24T00:00:00ZFais, A.Johnson, MarkWilson, M.Aguilar de Soto, NatachaMadsen, P. T.The sperm whale carries a hypertrophied nose that generates powerful clicks for long-range echolocation. However, it remains a conundrum how this bizarrely shaped apex predator catches its prey. Several hypotheses have been advanced to propose both active and passive means to acquire prey, including acoustic debilitation of prey with very powerful clicks. Here we test these hypotheses by using sound and movement recording tags in a fine-scale study of buzz sequences to relate the acoustic behaviour of sperm whales with changes in acceleration in their head region during prey capture attempts. We show that in the terminal buzz phase, sperm whales reduce inter-click intervals and estimated source levels by 1-2 orders of magnitude. As a result, received levels at the prey are more than an order of magnitude below levels required for debilitation, precluding acoustic stunning to facilitate prey capture. Rather, buzzing involves high-frequency, low amplitude clicks well suited to provide high-resolution biosonar updates during the last stages of capture. The high temporal resolution helps to guide motor patterns during occasionally prolonged chases in which prey are eventually subdued with the aid of fast jaw movements and/or buccal suction as indicated by acceleration transients (jerks) near the end of buzzes.Disturbance-specific social responses in long-finned pilot whales, Globicephala melashttp://hdl.handle.net/10023/9150
Social interactions among animals can influence their response to disturbance. We investigated responses of long-finned pilot whales to killer whale sound playbacks and two anthropogenic sources of disturbance: Tagging effort and naval sonar exposure. The acoustic scene and diving behaviour of tagged individuals were recorded along with the social behaviour of their groups. All three disturbance types resulted in larger group sizes, increasing social cohesion during disturbance. However, the nature and magnitude of other responses differed between disturbance types. Tagging effort resulted in a clear increase in synchrony and a tendency to reduce surface logging and to become silent (21% of cases), whereas pilot whales increased surface resting during sonar exposure. Killer whale sounds elicited increased calling rates and the aggregation of multiple groups, which approached the sound source together. This behaviour appears to represent a mobbing response, a likely adaptive social defence against predators or competitors. All observed response-Tactics would reduce risk of loss of group coordination, suggesting that, in social pilot whales, this could drive behavioural responses to disturbance. However, the behavioural means used to achieve social coordination depends upon other considerations, which are disturbance-specific.
The study was funded by the US Office of Naval Research, The Netherlands Ministry of Defence, Norwegian Ministry of Defence and French Ministry of Defence. F.V., C.C., P.K., F.P.L. and P.M. were supported by one or two of these funders. P.T. received funding from the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland). MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions.
Wed, 29 Jun 2016 00:00:00 GMThttp://hdl.handle.net/10023/91502016-06-29T00:00:00ZVisser, FleurCuré, CharlotteKvadsheim, Petter H.Lam, Frans-Peter A.Tyack, Peter L.Miller, Patrick J OSocial interactions among animals can influence their response to disturbance. We investigated responses of long-finned pilot whales to killer whale sound playbacks and two anthropogenic sources of disturbance: Tagging effort and naval sonar exposure. The acoustic scene and diving behaviour of tagged individuals were recorded along with the social behaviour of their groups. All three disturbance types resulted in larger group sizes, increasing social cohesion during disturbance. However, the nature and magnitude of other responses differed between disturbance types. Tagging effort resulted in a clear increase in synchrony and a tendency to reduce surface logging and to become silent (21% of cases), whereas pilot whales increased surface resting during sonar exposure. Killer whale sounds elicited increased calling rates and the aggregation of multiple groups, which approached the sound source together. This behaviour appears to represent a mobbing response, a likely adaptive social defence against predators or competitors. All observed response-Tactics would reduce risk of loss of group coordination, suggesting that, in social pilot whales, this could drive behavioural responses to disturbance. However, the behavioural means used to achieve social coordination depends upon other considerations, which are disturbance-specific.Vocal Learning and Auditory-Vocal Feedbackhttp://hdl.handle.net/10023/9082
Vocal learning is usually studied in songbirds and humans, species that can form auditory templates by listening to acoustic models and then learn to vocalize to match the template. Most other species are thought to develop vocalizations without auditory feedback. However, auditory input influences the acoustic structure of vocalizations in a broad distribution of birds and mammals. Vocalizations are dened here as sounds generated by forcing air past vibrating membranes. A vocal motor program may generate vocalizations such as crying or laughter, but auditory feedback may be required for matching precise acoustic features of vocalizations. This chapter discriminates limited vocal learning, which uses auditory input to fine-tune acoustic features of an inherited auditory template, from complex vocal learning, in which novel sounds are learned by matching a learned auditory template. Two or three songbird taxa and four or ve mammalian taxa are known for complex vocal learning. A broader range of mammals converge in the acoustic structure of vocalizations when in socially interacting groups, which qualifies as limited vocal learning. All birds and mammals tested use auditory-vocal feedback to adjust their vocalizations to compensate for the effects of noise, and many species modulate their signals as the costs and benefits of communicating vary. This chapter asks whether some auditory-vocal feedback may have provided neural substrates for the evolution of vocal learning. Progress will require more precise definitions of different forms of vocal learning, broad comparative review of their presence and absence, and behavioral and neurobiological investigations into the mechanisms underlying the skills.
Fri, 01 Jan 2016 00:00:00 GMThttp://hdl.handle.net/10023/90822016-01-01T00:00:00ZTyack, Peter LloydVocal learning is usually studied in songbirds and humans, species that can form auditory templates by listening to acoustic models and then learn to vocalize to match the template. Most other species are thought to develop vocalizations without auditory feedback. However, auditory input influences the acoustic structure of vocalizations in a broad distribution of birds and mammals. Vocalizations are dened here as sounds generated by forcing air past vibrating membranes. A vocal motor program may generate vocalizations such as crying or laughter, but auditory feedback may be required for matching precise acoustic features of vocalizations. This chapter discriminates limited vocal learning, which uses auditory input to fine-tune acoustic features of an inherited auditory template, from complex vocal learning, in which novel sounds are learned by matching a learned auditory template. Two or three songbird taxa and four or ve mammalian taxa are known for complex vocal learning. A broader range of mammals converge in the acoustic structure of vocalizations when in socially interacting groups, which qualifies as limited vocal learning. All birds and mammals tested use auditory-vocal feedback to adjust their vocalizations to compensate for the effects of noise, and many species modulate their signals as the costs and benefits of communicating vary. This chapter asks whether some auditory-vocal feedback may have provided neural substrates for the evolution of vocal learning. Progress will require more precise definitions of different forms of vocal learning, broad comparative review of their presence and absence, and behavioral and neurobiological investigations into the mechanisms underlying the skills.Novel application of a quantitative spatial comparison tool to species distribution datahttp://hdl.handle.net/10023/8985
Comparing geographically referenced maps has become an important aspect of spatial ecology (e.g. assessing change in distribution over time). Whilst humans are adept at recognising and extracting structure from maps (i.e. identifying spatial patterns), quantifying these structures can be difficult. Here, we show how the Structural Similarity (SSIM) index, a spatial comparison method adapted from techniques developed in computer science to determine the quality of image compression, can be used to extract additional information from spatial ecological data. We enhance the SSIM index to incorporate uncertainty from the underlyin g spatial models, and provide a software algorithm to correct for internal edge effects so that loss of spatial information from the map comparison is limited. The SSIM index uses a spatially-local window to calculate statistics based on local mean, variance, and covariance between the maps being compared. A number of statistics can be calculated using the SSIM index, ranging from a single summary statistic to quantify similarities between two maps, to maps of similarities in mean, variance, and covariance that can provide additional insight into underlying biological processes. We demonstrate the applicability of the SSIM approach using a case study of sperm whales in the Mediterranean Sea and identify areas where local-scale differences in space-use between groups and singleton whales occur. We show how novel insights into spatial structure can be extracted, which could not be obtained by visual inspection or cell-by-cell subtraction. As an approach, SSIM is applicable to a broad range of spatial ecological data, providing a novel, implementable tool for map comparison.
E.L.J. was funded under Scottish Government grant MMSS001/11. Sperm whale data were collected with support from One World Wildlife, the Natural Environment Research Council (NER/I/S/2002/00632), Whale and Dolphin Conservation (WDC), and J.M. Brotons of the Balearic Government Office of Fisheries Management. L.R. was supported by the MASTS pooling initiative, funded by the Scottish Funding Council (HR09011) and contributing institutions and their support are gratefully acknowledged.
Tue, 01 Nov 2016 00:00:00 GMThttp://hdl.handle.net/10023/89852016-11-01T00:00:00ZJones, Esther LaneRendell, Luke EdwardPirotta, EnricoLong, Jed A.Comparing geographically referenced maps has become an important aspect of spatial ecology (e.g. assessing change in distribution over time). Whilst humans are adept at recognising and extracting structure from maps (i.e. identifying spatial patterns), quantifying these structures can be difficult. Here, we show how the Structural Similarity (SSIM) index, a spatial comparison method adapted from techniques developed in computer science to determine the quality of image compression, can be used to extract additional information from spatial ecological data. We enhance the SSIM index to incorporate uncertainty from the underlyin g spatial models, and provide a software algorithm to correct for internal edge effects so that loss of spatial information from the map comparison is limited. The SSIM index uses a spatially-local window to calculate statistics based on local mean, variance, and covariance between the maps being compared. A number of statistics can be calculated using the SSIM index, ranging from a single summary statistic to quantify similarities between two maps, to maps of similarities in mean, variance, and covariance that can provide additional insight into underlying biological processes. We demonstrate the applicability of the SSIM approach using a case study of sperm whales in the Mediterranean Sea and identify areas where local-scale differences in space-use between groups and singleton whales occur. We show how novel insights into spatial structure can be extracted, which could not be obtained by visual inspection or cell-by-cell subtraction. As an approach, SSIM is applicable to a broad range of spatial ecological data, providing a novel, implementable tool for map comparison.Corkscrew seals : grey seal (Halichoerus grypus) infanticide and cannibalism may indicate the cause of spiral lacerations in sealshttp://hdl.handle.net/10023/8958
Large numbers of dead seals with characteristic spiral lesions have been washing ashore around the North Atlantic over the past two decades. Interactions with ship propellers and shark predation have been suggested as the likely causal mechanisms. However, new evidence points towards a more likely candidate: grey seal predation. An adult male grey seal was observed and recorded catching, killing and eating five weaned grey seal pups over a period of one week on the Isle of May, Scotland. A further 9 carcasses found in the same area exhibited similar injuries. Post mortem analysis of lesions indicated the wound characteristics were similar to each other and in 12 of the 14 carcasses analysed, were indistinguishable from carcasses previously attributed to propeller interaction. We therefore propose that most of the seal carcasses displaying spiral lacerations in the UK are caused by grey seal predation. Cases in other locations should be re-evaluated using the scoring system presented here to identify whether grey seal predation is a major cause of mortality in phocid seals.
This work was funded by Marine Scotland (http://www.gov.scot/Topics/marine/Publications/TopicSheets/MSScience, project: MMS001/11) and additionally supported by National Capability funding from the Natural Environment Research Council (http://www.nerc.ac.uk/) to the Sea Mammal Research Unit (grant no. SMRU1001).
Thu, 02 Jun 2016 00:00:00 GMThttp://hdl.handle.net/10023/89582016-06-02T00:00:00ZBrownlow, AndrewOnoufriou, JosephBishop, AmandaDavison, NicholasThompson, DaveLarge numbers of dead seals with characteristic spiral lesions have been washing ashore around the North Atlantic over the past two decades. Interactions with ship propellers and shark predation have been suggested as the likely causal mechanisms. However, new evidence points towards a more likely candidate: grey seal predation. An adult male grey seal was observed and recorded catching, killing and eating five weaned grey seal pups over a period of one week on the Isle of May, Scotland. A further 9 carcasses found in the same area exhibited similar injuries. Post mortem analysis of lesions indicated the wound characteristics were similar to each other and in 12 of the 14 carcasses analysed, were indistinguishable from carcasses previously attributed to propeller interaction. We therefore propose that most of the seal carcasses displaying spiral lacerations in the UK are caused by grey seal predation. Cases in other locations should be re-evaluated using the scoring system presented here to identify whether grey seal predation is a major cause of mortality in phocid seals.Circumpolar habitat use in the southern elephant seal: implications for foraging success and population trajectorieshttp://hdl.handle.net/10023/8892
In the Southern Ocean, wide-ranging predators offer the opportunity to quantify how animals respond to differences in the environment because their behavior and population trends are an integrated signal of prevailing conditions within multiple marine habitats. Southern elephant seals in particular, can provide useful insights due to their circumpolar distribution, their long and distant migrations and their performance of extended bouts of deep diving. Furthermore, across their range, elephant seal populations have very different population trends. In this study, we present a data set from the International Polar Year project; Marine Mammals Exploring the Oceans Pole to Pole for southern elephant seals, in which a large number of instruments (N = 287) deployed on animals, encompassing a broad circum-Antarctic geographic extent, collected in situ ocean data and at-sea foraging metrics that explicitly link foraging behavior and habitat structure in time and space. Broadly speaking, the seals foraged in two habitats, the relatively shallow waters of the Antarctic continental shelf and the Kerguelen Plateau and deep open water regions. Animals of both sexes were more likely to exhibit area-restricted search (ARS) behavior rather than transit in shelf habitats. While Antarctic shelf waters can be regarded as prime habitat for both sexes, female seals tend to move northwards with the advance of sea ice in the late autumn or early winter. The water masses used by the seals also influenced their behavioral mode, with female ARS behavior being most likely in modified Circumpolar Deepwater or northerly Modified Shelf Water, both of which tend to be associated with the outer reaches of the Antarctic Continental Shelf. The combined effects of (1) the differing habitat quality, (2) differing responses to encroaching ice as the winter progresses among colonies, (3) differing distances between breeding and haul-out sites and high quality habitats, and (4) differing long-term regional trends in sea ice extent can explain the differing population trends observed among elephant seal colonies.
Thu, 26 May 2016 00:00:00 GMThttp://hdl.handle.net/10023/88922016-05-26T00:00:00ZHindell, Mark A.McMahon, Clive R.Bester, Marthán N.Boehme, LarsCosta, DanielFedak, MikeGuinet, ChristopheHerraiz-Borreguero, LauraHarcourt, Robert G.Huckstadt, LuisKovacs, Kit M.Lydersen, ChristianMcInytre, TrevorMuelbert, MonicaRoquet, FabienWilliams, GuyCharrassin, Jean-BenoitIn the Southern Ocean, wide-ranging predators offer the opportunity to quantify how animals respond to differences in the environment because their behavior and population trends are an integrated signal of prevailing conditions within multiple marine habitats. Southern elephant seals in particular, can provide useful insights due to their circumpolar distribution, their long and distant migrations and their performance of extended bouts of deep diving. Furthermore, across their range, elephant seal populations have very different population trends. In this study, we present a data set from the International Polar Year project; Marine Mammals Exploring the Oceans Pole to Pole for southern elephant seals, in which a large number of instruments (N = 287) deployed on animals, encompassing a broad circum-Antarctic geographic extent, collected in situ ocean data and at-sea foraging metrics that explicitly link foraging behavior and habitat structure in time and space. Broadly speaking, the seals foraged in two habitats, the relatively shallow waters of the Antarctic continental shelf and the Kerguelen Plateau and deep open water regions. Animals of both sexes were more likely to exhibit area-restricted search (ARS) behavior rather than transit in shelf habitats. While Antarctic shelf waters can be regarded as prime habitat for both sexes, female seals tend to move northwards with the advance of sea ice in the late autumn or early winter. The water masses used by the seals also influenced their behavioral mode, with female ARS behavior being most likely in modified Circumpolar Deepwater or northerly Modified Shelf Water, both of which tend to be associated with the outer reaches of the Antarctic Continental Shelf. The combined effects of (1) the differing habitat quality, (2) differing responses to encroaching ice as the winter progresses among colonies, (3) differing distances between breeding and haul-out sites and high quality habitats, and (4) differing long-term regional trends in sea ice extent can explain the differing population trends observed among elephant seal colonies.Avoidance of wind farms by harbour seals is limited to pile driving activitieshttp://hdl.handle.net/10023/8856
1. As part of global efforts to reduce dependence on carbon-based energy sources there has been a rapid increase in the installation of renewable energy devices. The installation and operation of these devices can result in conflicts with wildlife. In the marine environment, mammals may avoid wind farms that are under construction or operating. Such avoidance may lead to more time spent travelling or displacement from key habitats. A paucity of data on at-sea movements of marine mammals around wind farms limits our understanding of the nature of their potential impacts. 2. Here, we present the results of a telemetry study on harbour seals Phoca vitulina in The Wash, south-east England, an area where wind farms are being constructed using impact pile driving. We investigated whether seals avoid wind farms during operation, construction in its entirety, or during piling activity. The study was carried out using historical telemetry data collected prior to any wind farm development and telemetry data collected in 2012 during the construction of one wind farm and the operation of another. 3. Within an operational wind farm, there was a close-to-significant increase in seal usage compared to prior to wind farm development. However, the wind farm was at the edge of a large area of increased usage, so the presence of the wind farm was unlikely to be the cause. 4. There was no significant displacement during construction as a whole. However, during piling, seal usage (abundance) was significantly reduced up to 25 km from the piling activity; within 25 km of the centre of the wind farm, there was a 19 to 83% (95% confidence intervals) decrease in usage compared to during breaks in piling, equating to a mean estimated displacement of 440 individuals. This amounts to significant displacement starting from predicted received levels of between 166 and 178 dB re 1 μPa(p·p). Displacement was limited to piling activity; within 2 h of cessation of pile driving, seals were distributed as per the non-piling scenario. 5. Synthesis and applications. Our spatial and temporal quantification of avoidance of wind farms by harbour seals is critical to reduce uncertainty and increase robustness in environmental impact assessments of future developments. Specifically, the results will allow policymakers to produce industry guidance on the likelihood of displacement of seals in response to pile driving; the relationship between sound levels and avoidance rates; and the duration of any avoidance, thus allowing far more accurate environmental assessments to be carried out during the consenting process. Further, our results can be used to inform mitigation strategies in terms of both the sound levels likely to cause displacement and what temporal patterns of piling would minimize the magnitude of the energetic impacts of displacement.
DJFR, GH, VMJ and BM were funded by the UK Department of Energy and Climate Change (DECC) as part of their Offshore Energy Strategic Environmental Assessment programme. DT and GH were also funded by NERC/Defra EBAO NE/J004243/1. ELJ was funded under Scottish Government grant MMSS001/01. This work was also supported by National Capability funding from the Natural Environment Research Council to SMRU (grant no. SMRU1001). Tags and their deployment in the Thames in 2006 and The Wash were funded by DECC. Tags and their deployment in the Thames in 2012 were commissioned by Zoological Society London, with funding from BBC Wildlife Fund and Sita Trust.
Thu, 01 Dec 2016 00:00:00 GMThttp://hdl.handle.net/10023/88562016-12-01T00:00:00ZRussell, Deborah J. F.Hastie, Gordon D.Thompson, DavidJanik, Vincent M.Hammond, Philip S.Scott-Hayward, Lindesay A. S.Matthiopoulos, JasonJones, Esther L.McConnell, Bernie J.1. As part of global efforts to reduce dependence on carbon-based energy sources there has been a rapid increase in the installation of renewable energy devices. The installation and operation of these devices can result in conflicts with wildlife. In the marine environment, mammals may avoid wind farms that are under construction or operating. Such avoidance may lead to more time spent travelling or displacement from key habitats. A paucity of data on at-sea movements of marine mammals around wind farms limits our understanding of the nature of their potential impacts. 2. Here, we present the results of a telemetry study on harbour seals Phoca vitulina in The Wash, south-east England, an area where wind farms are being constructed using impact pile driving. We investigated whether seals avoid wind farms during operation, construction in its entirety, or during piling activity. The study was carried out using historical telemetry data collected prior to any wind farm development and telemetry data collected in 2012 during the construction of one wind farm and the operation of another. 3. Within an operational wind farm, there was a close-to-significant increase in seal usage compared to prior to wind farm development. However, the wind farm was at the edge of a large area of increased usage, so the presence of the wind farm was unlikely to be the cause. 4. There was no significant displacement during construction as a whole. However, during piling, seal usage (abundance) was significantly reduced up to 25 km from the piling activity; within 25 km of the centre of the wind farm, there was a 19 to 83% (95% confidence intervals) decrease in usage compared to during breaks in piling, equating to a mean estimated displacement of 440 individuals. This amounts to significant displacement starting from predicted received levels of between 166 and 178 dB re 1 μPa(p·p). Displacement was limited to piling activity; within 2 h of cessation of pile driving, seals were distributed as per the non-piling scenario. 5. Synthesis and applications. Our spatial and temporal quantification of avoidance of wind farms by harbour seals is critical to reduce uncertainty and increase robustness in environmental impact assessments of future developments. Specifically, the results will allow policymakers to produce industry guidance on the likelihood of displacement of seals in response to pile driving; the relationship between sound levels and avoidance rates; and the duration of any avoidance, thus allowing far more accurate environmental assessments to be carried out during the consenting process. Further, our results can be used to inform mitigation strategies in terms of both the sound levels likely to cause displacement and what temporal patterns of piling would minimize the magnitude of the energetic impacts of displacement.Bimodal winter haul-out patterns of adult Weddell seals (Leptonychotes weddellii) in the southern Weddell Seahttp://hdl.handle.net/10023/8843
Hauling out is an essential component of pinniped life-history. Haul-out behaviour may be affected by biological (e.g. sex, age and condition) and physical factors (e.g. food availability and environmental conditions), and identifying these factors may help explain the spatiotemporal distribution and habitat use of pinnipeds. The aim of this study is to describe observed winter haul-out patterns of adult Weddell seals in the Weddell Sea and investigate the role of potential predictors to gain insight into the way these animals interact with the physical environment in this region. We examined the haul-out behaviour in relation to available biological (i.e., diving effort, sex) and physical information (i.e., sun angle). Thirty-three satellite telemetry tags were deployed on adult Weddell seals in the southern Weddell Sea during February 2007, 2009 and 2011, following their annual moult recording information on the behavioural mode f the animal: at surface, hauled out or diving. At the end of the austral summer Weddell seals spent, on average, more than 40% of their time hauled out on the ice. Under constant light conditions, it appears that physiological factors drive sex differences in the timing and duration of haul-out behaviour, with females spending on average more time hauled out than males during daylight hours. This time spent hauled-out declined to around 15% in both sexes by the beginning of autumn and remained at this level with a clear nocturnal haul-out pattern during the winter. The time spent diving increased during this period, indicating an increase in foraging effort during the winter months, and led to a common haul-out pattern in both sexes over winter. We found a positive relationship between haul-out duration and the percentage of time spent diving prior to a haul-out in both sexes, with the exception of female daytime haul-outs early in the year.
This research was funded by NERC grants NE/G014833/1 and NE/G014086/1 and also received funding from the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland) and their support is gratefully acknowledged. MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions. During the completion of the manuscript preparation TP was supported by a South African National Research Foundation Scarce Skills postdoctoral research fellowship.
Thu, 19 May 2016 00:00:00 GMThttp://hdl.handle.net/10023/88432016-05-19T00:00:00ZBoehme, LarsBaker, AmyFedak, MikeÅrthun, MariusNicholls, KeithRobinson, PatrickCosta, DanBiuw, MartinPhotopoulou, TheoniHauling out is an essential component of pinniped life-history. Haul-out behaviour may be affected by biological (e.g. sex, age and condition) and physical factors (e.g. food availability and environmental conditions), and identifying these factors may help explain the spatiotemporal distribution and habitat use of pinnipeds. The aim of this study is to describe observed winter haul-out patterns of adult Weddell seals in the Weddell Sea and investigate the role of potential predictors to gain insight into the way these animals interact with the physical environment in this region. We examined the haul-out behaviour in relation to available biological (i.e., diving effort, sex) and physical information (i.e., sun angle). Thirty-three satellite telemetry tags were deployed on adult Weddell seals in the southern Weddell Sea during February 2007, 2009 and 2011, following their annual moult recording information on the behavioural mode f the animal: at surface, hauled out or diving. At the end of the austral summer Weddell seals spent, on average, more than 40% of their time hauled out on the ice. Under constant light conditions, it appears that physiological factors drive sex differences in the timing and duration of haul-out behaviour, with females spending on average more time hauled out than males during daylight hours. This time spent hauled-out declined to around 15% in both sexes by the beginning of autumn and remained at this level with a clear nocturnal haul-out pattern during the winter. The time spent diving increased during this period, indicating an increase in foraging effort during the winter months, and led to a common haul-out pattern in both sexes over winter. We found a positive relationship between haul-out duration and the percentage of time spent diving prior to a haul-out in both sexes, with the exception of female daytime haul-outs early in the year.Sound exposure in harbour seals during the installation of an offshore wind farm : predictions of auditory damagehttp://hdl.handle.net/10023/8838
Summary 1. With ambitious renewable energy targets, pile driving associated with offshore wind farm construction will become widespread in the marine environment. Many proposed wind farms overlap with the distribution of seals, and sound from pile driving has the potential to cause auditory damage. 2. We report on a behavioural study during the construction of a wind farm using data from GPS/GSM tags on 24 harbour seals Phoca vitulina L. Pile driving data and acoustic propagation models, together with seal movement and dive data, allowed the prediction of auditory damage in each seal. 3. Growth and recovery functions for auditory damage were combined to predict temporary auditory threshold shifts in each seal. Further, M-weighted cumulative sound exposure levels [cSELs(Mpw)] were calculated and compared to permanent auditory threshold shift exposure criteria for pinnipeds in water exposed to pulsed sounds. 4. The closest distance of each seal to pile driving varied from 47 to 405 km, and predicted maximum cSELs(Mpw) ranged from 170.7 to 195.3 dB re 1μPa2 -s for individual seals. Comparison to exposure criteria suggests that half of the seals exceeded estimated permanent auditory damage thresholds. 5. Prediction of auditory damage in marine mammals is a rapidly evolving field and has number of key uncertainties associated with it. These include how sound propagates in shallow water environments and the effects of pulsed sounds on seal hearing; as such, our predictions should be viewed in this context. 6. Policy implications. We predicted that half of the tagged seals received sound levels from pile driving that exceeded auditory damage thresholds for pinnipeds. These results have implications for offshore industry and will be important for policymakers developing guidance for pile driving. Developing engineering solutions to reduce sound levels at source or methods to deter animals from damage risk zones, or changing temporal patterns of piling could potentially reduce auditory damage risk. Future work should focus on validating these predictions by collecting auditory threshold information pre- and post-exposure to pile driving. Ultimately, information on population-level impacts of exposure to pile driving is required to ensure that offshore industry is developed in an environmentally sustainable manner.
The work was funded by the Department as part of its Strategic Environmental Assessment programme. In addition, support for D. Thompson was provided by the Natural Environment Research Council EBAO project.
Mon, 01 Jun 2015 00:00:00 GMThttp://hdl.handle.net/10023/88382015-06-01T00:00:00ZHastie, Gordon DrummondRussell, Deborah Jill FraserMcConnell, Bernie JMoss, SimonThompson, DavidJanik, Vincent M.Summary 1. With ambitious renewable energy targets, pile driving associated with offshore wind farm construction will become widespread in the marine environment. Many proposed wind farms overlap with the distribution of seals, and sound from pile driving has the potential to cause auditory damage. 2. We report on a behavioural study during the construction of a wind farm using data from GPS/GSM tags on 24 harbour seals Phoca vitulina L. Pile driving data and acoustic propagation models, together with seal movement and dive data, allowed the prediction of auditory damage in each seal. 3. Growth and recovery functions for auditory damage were combined to predict temporary auditory threshold shifts in each seal. Further, M-weighted cumulative sound exposure levels [cSELs(Mpw)] were calculated and compared to permanent auditory threshold shift exposure criteria for pinnipeds in water exposed to pulsed sounds. 4. The closest distance of each seal to pile driving varied from 47 to 405 km, and predicted maximum cSELs(Mpw) ranged from 170.7 to 195.3 dB re 1μPa2 -s for individual seals. Comparison to exposure criteria suggests that half of the seals exceeded estimated permanent auditory damage thresholds. 5. Prediction of auditory damage in marine mammals is a rapidly evolving field and has number of key uncertainties associated with it. These include how sound propagates in shallow water environments and the effects of pulsed sounds on seal hearing; as such, our predictions should be viewed in this context. 6. Policy implications. We predicted that half of the tagged seals received sound levels from pile driving that exceeded auditory damage thresholds for pinnipeds. These results have implications for offshore industry and will be important for policymakers developing guidance for pile driving. Developing engineering solutions to reduce sound levels at source or methods to deter animals from damage risk zones, or changing temporal patterns of piling could potentially reduce auditory damage risk. Future work should focus on validating these predictions by collecting auditory threshold information pre- and post-exposure to pile driving. Ultimately, information on population-level impacts of exposure to pile driving is required to ensure that offshore industry is developed in an environmentally sustainable manner.Breeding male grey seals exhibit similar activity budgets across varying exposures to human activityhttp://hdl.handle.net/10023/8751
Human-wildlife interactions can be incidental or direct through activities such as wildlife tourism. In the presence of anthropogenic activities, some animals exhibit behavioural alterations such as increased vigilance or spatial displacement. Thus, chronic exposure could be adverse to individual fitness through loss of energy or time. Pinnipeds are exposed to human activities in the aquatic environment and on land, but the degree of exposure varies across a species' geographic distribution. For example, breeding colonies of grey seals Halichoerus grypus along the mainland coast of England are exposed to anthropogenic disturbance in the forms of tourism and military activities; however, many offshore colonies are relatively undisturbed. Due to the recent expansion of mainland colonies, the impacts of human presence during the breeding season are of urgent interest for managers. Therefore, the aim of this study was to test for any behavioural adjustments associated with anthropogenic presence by comparing the activity budgets of individual male grey seals at a mainland colony with activity budgets from 2 isolated colonies. We found no evidence of differences in the male activity budgets for time spent in non-active behaviours across colonies, and of the 3 colonies, males on the mainland spent the least amount of time alert. This indicates that as capital breeders, selection for conservation of energy is potentially overriding short-term costs of local stressors or that males at the mainland colony have habituated to human presence. Our results demonstrate the importance of understanding species-and life history-stage-specific selection pressures when considering management actions.
Thu, 07 May 2015 00:00:00 GMThttp://hdl.handle.net/10023/87512015-05-07T00:00:00ZBishop, AmandaPomeroy, PatrickTwiss, Sean D.Human-wildlife interactions can be incidental or direct through activities such as wildlife tourism. In the presence of anthropogenic activities, some animals exhibit behavioural alterations such as increased vigilance or spatial displacement. Thus, chronic exposure could be adverse to individual fitness through loss of energy or time. Pinnipeds are exposed to human activities in the aquatic environment and on land, but the degree of exposure varies across a species' geographic distribution. For example, breeding colonies of grey seals Halichoerus grypus along the mainland coast of England are exposed to anthropogenic disturbance in the forms of tourism and military activities; however, many offshore colonies are relatively undisturbed. Due to the recent expansion of mainland colonies, the impacts of human presence during the breeding season are of urgent interest for managers. Therefore, the aim of this study was to test for any behavioural adjustments associated with anthropogenic presence by comparing the activity budgets of individual male grey seals at a mainland colony with activity budgets from 2 isolated colonies. We found no evidence of differences in the male activity budgets for time spent in non-active behaviours across colonies, and of the 3 colonies, males on the mainland spent the least amount of time alert. This indicates that as capital breeders, selection for conservation of energy is potentially overriding short-term costs of local stressors or that males at the mainland colony have habituated to human presence. Our results demonstrate the importance of understanding species-and life history-stage-specific selection pressures when considering management actions.Gauging allowable harm limits to cumulative, sub-lethal effects of human activities on wildlife : a case-study approach using two whale populationshttp://hdl.handle.net/10023/8716
As sublethal human pressures on marine wildlife and their habitats increase and interact in complex ways, there is a pressing need for methods to quantify cumulative impacts of these stressors on populations, and policy decisions about allowable harm limits. Few studies quantify population consequences of individual stressors, and fewer quantify synergistic effects. Incorporating all sources of uncertainty can cause predictions to span the range from negligible to catastrophic. Two places were identified to bound this problem through energetic mechanisms that reduce prey available to individuals. First, the US Marine Mammal Protection Act's Potential Biological Removal (PBR) equation was used as a placeholder allowable harm limit to represent the number of animals that can be removed annually without depleting a population below agreed-upon management targets. That rephrased the research question from, “How big could cumulative impacts be?” to “How big would cumulative impacts have to be to exceed an agreed-upon threshold?” Secondly, two data-rich case studies, namely Gulf of Maine humpback and northeast Pacific resident killer whales, were used as examples to parameterize the weakest link, namely between prey availability and demography. Given no additional information, the model predicted that human activities need only reduce prey available to the killer whale population by ~10% to cause a population-level take, through reduced fecundity and/or survival, equivalent to PBR. By contrast, in the humpback population, reduction in prey availability of ~50% was needed to cause a similar, PBR-sized effect. The paper describes an approach – results are merely illustrative. The two case studies differ in prey specialization, life history, and, no doubt, proximity to carrying capacity. This method of inverting the problem refocuses discussions around what the level of prey depletion – via competition with commercial fisheries, displacement from feeding areas through noise-generating activities, or acoustic masking of signals used to detect prey – would have to occur to exceed allowable harm limits set for lethal takes in fisheries or other, more easily quantifiable, human activities.
Rob Williams was supported by a Marie Curie International Incoming Fellowship within the 7th European Community Framework Programme (Project CONCEAL, FP7, PIIF-GA-2009-253407).
Mon, 01 Aug 2016 00:00:00 GMThttp://hdl.handle.net/10023/87162016-08-01T00:00:00ZWilliams, RobThomas, LenAshe, ErinClark, Christopher W.Hammond, Philip S.As sublethal human pressures on marine wildlife and their habitats increase and interact in complex ways, there is a pressing need for methods to quantify cumulative impacts of these stressors on populations, and policy decisions about allowable harm limits. Few studies quantify population consequences of individual stressors, and fewer quantify synergistic effects. Incorporating all sources of uncertainty can cause predictions to span the range from negligible to catastrophic. Two places were identified to bound this problem through energetic mechanisms that reduce prey available to individuals. First, the US Marine Mammal Protection Act's Potential Biological Removal (PBR) equation was used as a placeholder allowable harm limit to represent the number of animals that can be removed annually without depleting a population below agreed-upon management targets. That rephrased the research question from, “How big could cumulative impacts be?” to “How big would cumulative impacts have to be to exceed an agreed-upon threshold?” Secondly, two data-rich case studies, namely Gulf of Maine humpback and northeast Pacific resident killer whales, were used as examples to parameterize the weakest link, namely between prey availability and demography. Given no additional information, the model predicted that human activities need only reduce prey available to the killer whale population by ~10% to cause a population-level take, through reduced fecundity and/or survival, equivalent to PBR. By contrast, in the humpback population, reduction in prey availability of ~50% was needed to cause a similar, PBR-sized effect. The paper describes an approach – results are merely illustrative. The two case studies differ in prey specialization, life history, and, no doubt, proximity to carrying capacity. This method of inverting the problem refocuses discussions around what the level of prey depletion – via competition with commercial fisheries, displacement from feeding areas through noise-generating activities, or acoustic masking of signals used to detect prey – would have to occur to exceed allowable harm limits set for lethal takes in fisheries or other, more easily quantifiable, human activities.Gait switches in deep-diving beaked whales : biomechanical strategies for long-duration diveshttp://hdl.handle.net/10023/8712
Diving animals modulate their swimming gaits to promote locomotor efficiency and so enable longer, more productive dives. Beaked whales perform extremely long and deep foraging dives that probably exceed aerobic capacities for some species. Here, we use biomechanical data from suction-cup tags attached to three species of beaked whales (Mesoplodon densirostris, N = 10; Ziphius cavirostris, N = 9; and Hyperoodon ampullatus, N = 2) to characterize their swimming gaits. In addition to continuous stroking and stroke and-glide gaits described for other diving mammals, all whales produced occasional fluke-strokes with distinctly larger dorsoventral acceleration, which we termed 'type-B' strokes. These high-power strokes occurred almost exclusively during deep dive ascents as part of a novel mixed gait. To quantify body rotations and specific acceleration generated during strokes we adapted a kinematic method combining data from two sensors in the tag. Body rotations estimated with high-rate magnetometer data were subtracted from accelerometer data to estimate the resulting surge and heave accelerations. Using this method, we show that stroke duration, rotation angle and acceleration were bi-modal for these species, with B-strokes having 76% of the duration, 52% larger body rotation and four times more surge than normal strokes. The additional acceleration of B-strokes did not lead to faster ascents, but rather enabled brief glides, which may improve the overall efficiency of this gait. Their occurrence towards the end of long dives leads us to propose that B-strokes may recruit fast-twitch fibres that comprise similar to 80% of swimming muscles in Blainville's beaked whales, thus prolonging foraging time at depth.
Work in the Canary Islands was funded by the Office of Naval Research and the National Oceanographic Partnership Program (NOPP), by a consortium consisting of the Canary Islands Government, the Spanish Ministry of Environment and the Spanish Ministry of Defense and by the European environmental funding LIFE-INDEMARES program for the inventory and designation of the Natura 2000 network in marine areas of the Spanish territory, headed by Fundacion Biodiversidad, with additional support from the Cabildo Insular of El Hierro. Fieldwork in the Ligurian Sea was funded by NOPP. Research in the Gully was funded by the Strategic Environmental Research and Development Program (SERDP) programs RC-2113 and RC-2337. L.M.M.L. was funded by a ‘la Caixa’ Fellowship within the 2010 UK Framework Programme. N.A.d.S. was funded for this study by ONR and by the EU FP7 Marie Curie project SOUNDMAR. M.J. was funded by a Marie Curie Career Integration Grant, and from the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland) and their support is gratefully acknowledged. MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions.
Fri, 01 May 2015 00:00:00 GMThttp://hdl.handle.net/10023/87122015-05-01T00:00:00ZMartin Lopez, Lucia MartinaMiller, Patrick J. O.de Soto, Natacha AguilarJohnson, MarkDiving animals modulate their swimming gaits to promote locomotor efficiency and so enable longer, more productive dives. Beaked whales perform extremely long and deep foraging dives that probably exceed aerobic capacities for some species. Here, we use biomechanical data from suction-cup tags attached to three species of beaked whales (Mesoplodon densirostris, N = 10; Ziphius cavirostris, N = 9; and Hyperoodon ampullatus, N = 2) to characterize their swimming gaits. In addition to continuous stroking and stroke and-glide gaits described for other diving mammals, all whales produced occasional fluke-strokes with distinctly larger dorsoventral acceleration, which we termed 'type-B' strokes. These high-power strokes occurred almost exclusively during deep dive ascents as part of a novel mixed gait. To quantify body rotations and specific acceleration generated during strokes we adapted a kinematic method combining data from two sensors in the tag. Body rotations estimated with high-rate magnetometer data were subtracted from accelerometer data to estimate the resulting surge and heave accelerations. Using this method, we show that stroke duration, rotation angle and acceleration were bi-modal for these species, with B-strokes having 76% of the duration, 52% larger body rotation and four times more surge than normal strokes. The additional acceleration of B-strokes did not lead to faster ascents, but rather enabled brief glides, which may improve the overall efficiency of this gait. Their occurrence towards the end of long dives leads us to propose that B-strokes may recruit fast-twitch fibres that comprise similar to 80% of swimming muscles in Blainville's beaked whales, thus prolonging foraging time at depth.Population structure of humpback whales in the western and central South Pacific Ocean as determined by vocal exchange among populationshttp://hdl.handle.net/10023/8568
For cetaceans, population structure is traditionally determined by molecular genetics or photographically identified individuals. Acoustic data, however, has provided information on movement and population structure with less effort and cost than traditional methods in an array of taxa. Male humpback whales (Megaptera novaeangliae) produce a continually evolving vocal sexual display, or song, that is similar among all males in a population. The rapid cultural transmission (the transfer of information or behavior between conspecifics through social learning) of different versions of this display between distinct but interconnected populations in the western and central South Pacific region presents a unique way to investigate population structure based on the movement dynamics of a song (acoustic) display. Using 11 years of data, we investigated an acoustically based population structure for the region by comparing stereotyped song sequences among populations and years. We used the Levenshtein distance technique to group previously defined populations into (vocally based) clusters based on the overall similarity of their song display in space and time. We identified the following distinct vocal clusters: western cluster, 1 population off eastern Australia; central cluster, populations around New Caledonia, Tonga, and American Samoa; and eastern region, either a single cluster or 2 clusters, one around the Cook Islands and the other off French Polynesia. These results are consistent with the hypothesis that each breeding aggregation represents a distinct population (each occupied a single, terminal node) in a metapopulation, similar to the current understanding of population structure based on genetic and photo-identification studies. However, the central vocal cluster had higher levels of song-sharing among populations than the other clusters, indicating that levels of vocal connectivity varied within the region. Our results demonstrate the utility and value of using culturally transmitted vocal patterns as a way of defining connectivity to infer population structure. We suggest vocal patterns be incorporated by the International Whaling Commission in conjunction with traditional methods in the assessment of structure.
Sat, 01 Aug 2015 00:00:00 GMThttp://hdl.handle.net/10023/85682015-08-01T00:00:00ZGarland, Ellen C.Goldizen, Anne W.Lilley, Matthew S.Rekdahl, Melinda L.Garrigue, ClaireConstantine, RochelleHauser, Nan DaeschlerPoole, M. MichaelRobbins, JookeNoad, Michael J.For cetaceans, population structure is traditionally determined by molecular genetics or photographically identified individuals. Acoustic data, however, has provided information on movement and population structure with less effort and cost than traditional methods in an array of taxa. Male humpback whales (Megaptera novaeangliae) produce a continually evolving vocal sexual display, or song, that is similar among all males in a population. The rapid cultural transmission (the transfer of information or behavior between conspecifics through social learning) of different versions of this display between distinct but interconnected populations in the western and central South Pacific region presents a unique way to investigate population structure based on the movement dynamics of a song (acoustic) display. Using 11 years of data, we investigated an acoustically based population structure for the region by comparing stereotyped song sequences among populations and years. We used the Levenshtein distance technique to group previously defined populations into (vocally based) clusters based on the overall similarity of their song display in space and time. We identified the following distinct vocal clusters: western cluster, 1 population off eastern Australia; central cluster, populations around New Caledonia, Tonga, and American Samoa; and eastern region, either a single cluster or 2 clusters, one around the Cook Islands and the other off French Polynesia. These results are consistent with the hypothesis that each breeding aggregation represents a distinct population (each occupied a single, terminal node) in a metapopulation, similar to the current understanding of population structure based on genetic and photo-identification studies. However, the central vocal cluster had higher levels of song-sharing among populations than the other clusters, indicating that levels of vocal connectivity varied within the region. Our results demonstrate the utility and value of using culturally transmitted vocal patterns as a way of defining connectivity to infer population structure. We suggest vocal patterns be incorporated by the International Whaling Commission in conjunction with traditional methods in the assessment of structure.Sperm whales reduce foraging effort during exposure to 1-2 kH z sonar and killer whale soundshttp://hdl.handle.net/10023/8462
The time and energetic costs of behavioral responses to incidental and experimental sonar exposures, as well as control stimuli, were quantified using hidden state analysis of time series of acoustic and movement data recorded by tags (DTAG) attached to 12 sperm whales (Physeter macrocephalus) using suction cups. Behavioral state transition modeling showed that tagged whales switched to a non-foraging, non-resting state during both experimental transmissions of low-frequency active sonar from an approaching vessel (LFAS; 1-2 kH z, source level 214 dB re 1 μPa m, four tag records) and playbacks of potential predator (killer whale, Orcinus orca) sounds broadcast at naturally occurring sound levels as a positive control from a drifting boat (five tag records). Time spent in foraging states and the probability of prey capture attempts were reduced during these two types of exposures with little change in overall locomotion activity, suggesting an effect on energy intake with no immediate compensation. Whales switched to the active non-foraging state over received sound pressure levels of 131-165 dB re 1 μPa during LFAS exposure. In contrast, no changes in foraging behavior were detected in response to experimental negative controls (no-sonar ship approach or noise control playback) or to experimental medium-frequency active sonar exposures (MFAS; 6-7 kH z, source level 199 re 1 μPa m, received sound pressure level [SPL] = 73-158 dB re 1 μPa). Similarly, there was no reduction in foraging effort for three whales exposed to incidental, unidentified 4.7-5.1 kH z sonar signals received at lower levels (SPL = 89-133 dB re 1 μPa). These results demonstrate that similar to predation risk, exposure to sonar can affect functional behaviors, and indicate that increased perception of risk with higher source level or lower frequency may modulate how sperm whales respond to anthropogenic sound.
We would like to thank 3S partners and funders especially for enabling this research (NL Ministry of Defence, NOR Ministry of Defence, US Office of Naval Research, and World Wildlife Fund, Norway). PLT was supported by the Scottish Funding Council (grant HR09011) through the Marine Alliance for Science and Technology for Scotland.
Mon, 08 Feb 2016 00:00:00 GMThttp://hdl.handle.net/10023/84622016-02-08T00:00:00ZIsojunno, SaanaCuré, CharlotteKvadsheim, Petter HelgevoldLam, Frans-Peter AlexanderTyack, Peter LloydWensveen, Paul JacobusMiller, Patrick James O'MalleyThe time and energetic costs of behavioral responses to incidental and experimental sonar exposures, as well as control stimuli, were quantified using hidden state analysis of time series of acoustic and movement data recorded by tags (DTAG) attached to 12 sperm whales (Physeter macrocephalus) using suction cups. Behavioral state transition modeling showed that tagged whales switched to a non-foraging, non-resting state during both experimental transmissions of low-frequency active sonar from an approaching vessel (LFAS; 1-2 kH z, source level 214 dB re 1 μPa m, four tag records) and playbacks of potential predator (killer whale, Orcinus orca) sounds broadcast at naturally occurring sound levels as a positive control from a drifting boat (five tag records). Time spent in foraging states and the probability of prey capture attempts were reduced during these two types of exposures with little change in overall locomotion activity, suggesting an effect on energy intake with no immediate compensation. Whales switched to the active non-foraging state over received sound pressure levels of 131-165 dB re 1 μPa during LFAS exposure. In contrast, no changes in foraging behavior were detected in response to experimental negative controls (no-sonar ship approach or noise control playback) or to experimental medium-frequency active sonar exposures (MFAS; 6-7 kH z, source level 199 re 1 μPa m, received sound pressure level [SPL] = 73-158 dB re 1 μPa). Similarly, there was no reduction in foraging effort for three whales exposed to incidental, unidentified 4.7-5.1 kH z sonar signals received at lower levels (SPL = 89-133 dB re 1 μPa). These results demonstrate that similar to predation risk, exposure to sonar can affect functional behaviors, and indicate that increased perception of risk with higher source level or lower frequency may modulate how sperm whales respond to anthropogenic sound.Apparent source levels and active communication space of whistles of free-ranging Indo-Pacific humpback dolphins (Sousa chinensis) in the Pearl River Estuary and Beibu Gulf, Chinahttp://hdl.handle.net/10023/8449
Background . Knowledge of species-specific vocalization characteristics and their associated active communication space, the effective range over which a communication signal can be detected by a conspecific, is critical for understanding the impacts of underwater acoustic pollution, as well as other threats. Methods. We used a two-dimensional cross-shaped hydrophone array system to record the whistles of free-ranging Indo-Pacific humpback dolphins (Sousa chinensis) in shallow-water environments of the Pearl River Estuary (PRE) and Beibu Gulf (BG), China. Using hyperbolic position fixing, which exploits time differences of arrival of a signal between pairs of hydrophone receivers, we obtained source location estimates for whistles with good signal-to-noise ratio (SNR ≥ 10 dB) and not polluted by other sounds and back-calculated their apparent source levels (ASL). Combining with the masking levels (including simultaneous noise levels, masking tonal threshold, and the Sousa auditory threshold) and the custom made site-specific sound propagation models, we further estimated their active communication space (ACS). Results. Humpback dolphins produced whistles with average root-mean-square ASL of 138.5 ± 6.8 (mean ± standard deviation) and 137.2 ± 7.0 dB re 1 µPa in PRE (N = 33) and BG (N = 209), respectively. We found statistically significant differences in ASLs among different whistle contour types. The mean and maximum ACS of whistles were estimated to be 14.7 ± 2.6 (median ± quartile deviation) and 17.1 ± 3.5 m in PRE, and 34.2 ± 9.5 and 43.5 ±12.2 m in BG. Using just the auditory threshold as the masking level produced the mean and maximum ACSat of 24.3 ± 4.8 and 35.7 ± 4.6 m for PRE, and 60.7 ± 18.1 and 74.3 ± 25.3 m for BG. The small ACSs were due to the high ambient noise level. Significant differences in ACSs were also observed among different whistle contour types. Discussion. Besides shedding some light for evaluating appropriate noise exposure levels and information for the regulation of underwater acoustic pollution, these baseline data can also be used for aiding the passive acoustic monitoring of dolphin populations, defining the boundaries of separate groups in a more biologically meaningful way during field surveys, and guiding the appropriate approach distance for local dolphin-watching boats and research boat during focal group following.
Grants for this study was provided by the National Natural Science Foundation (NNSF) of China (Grant No.31070347), the Ministry of Science and Technology of China (Grant No. 2011BAG07B05-3), the Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No. KSCX2-EW-Z-4) and the Special Fund for Agro-scientific Research in the Public Interest of the Ministry of Agriculture of China (Grant No. 201203086) to DW, the State Oceanic Administration of China (Grant No. 201105011-3) and NNSF of China (Grant No. 31170501) to KXW and the China Scholarship Council (Grant No. (2014)3026) to ZTW.
Mon, 15 Feb 2016 00:00:00 GMThttp://hdl.handle.net/10023/84492016-02-15T00:00:00ZWang, Zhi-TaoAu, Whitlow W. L.Rendell, LukeWang, Ke-XiongWu, Hai-PingWu, Yu-PingLiu, Jian-ChangDuan, Guo-QinCao, Han-JiangWang, DingBackground . Knowledge of species-specific vocalization characteristics and their associated active communication space, the effective range over which a communication signal can be detected by a conspecific, is critical for understanding the impacts of underwater acoustic pollution, as well as other threats. Methods. We used a two-dimensional cross-shaped hydrophone array system to record the whistles of free-ranging Indo-Pacific humpback dolphins (Sousa chinensis) in shallow-water environments of the Pearl River Estuary (PRE) and Beibu Gulf (BG), China. Using hyperbolic position fixing, which exploits time differences of arrival of a signal between pairs of hydrophone receivers, we obtained source location estimates for whistles with good signal-to-noise ratio (SNR ≥ 10 dB) and not polluted by other sounds and back-calculated their apparent source levels (ASL). Combining with the masking levels (including simultaneous noise levels, masking tonal threshold, and the Sousa auditory threshold) and the custom made site-specific sound propagation models, we further estimated their active communication space (ACS). Results. Humpback dolphins produced whistles with average root-mean-square ASL of 138.5 ± 6.8 (mean ± standard deviation) and 137.2 ± 7.0 dB re 1 µPa in PRE (N = 33) and BG (N = 209), respectively. We found statistically significant differences in ASLs among different whistle contour types. The mean and maximum ACS of whistles were estimated to be 14.7 ± 2.6 (median ± quartile deviation) and 17.1 ± 3.5 m in PRE, and 34.2 ± 9.5 and 43.5 ±12.2 m in BG. Using just the auditory threshold as the masking level produced the mean and maximum ACSat of 24.3 ± 4.8 and 35.7 ± 4.6 m for PRE, and 60.7 ± 18.1 and 74.3 ± 25.3 m for BG. The small ACSs were due to the high ambient noise level. Significant differences in ACSs were also observed among different whistle contour types. Discussion. Besides shedding some light for evaluating appropriate noise exposure levels and information for the regulation of underwater acoustic pollution, these baseline data can also be used for aiding the passive acoustic monitoring of dolphin populations, defining the boundaries of separate groups in a more biologically meaningful way during field surveys, and guiding the appropriate approach distance for local dolphin-watching boats and research boat during focal group following.Single-click beam patterns suggest dynamic changes to the field of view of echolocating Atlantic Spotted Dolphins (Stenella frontalis) in the wildhttp://hdl.handle.net/10023/8414
Echolocating animals exercise an extensive control over the spectral and temporal properties of their biosonar signals to facilitate perception of their actively generated auditory scene when homing in on prey. The intensity and directionality of the biosonar beam defines the field of view of echolocating animals by affecting the acoustic detection range and angular coverage. However, the spatial relationship between an echolocating predator and its prey changes rapidly, resulting in different biosonar requirements throughout prey pursuit and capture. Here, we measured single-click beam patterns using a parametric fit procedure to test whether free-ranging Atlantic spotted dolphins (Stenella frontalis) modify their biosonar beam width. We recorded echolocation clicks using a linear array of receivers and estimated the beam width of individual clicks using a parametric spectral fit, cross-validated with well-established composite beam pattern estimates. The dolphins apparently increased the biosonar beam width, to a large degree without changing the signal frequency, when they approached the recording array. This is comparable to bats that also expand their field of view during prey capture, but achieve this by decreasing biosonar frequency. This behaviour may serve to decrease the risk that rapid escape movements of prey take them outside the biosonar beam of the predator. It is likely that shared sensory requirements have resulted in bats and toothed whales expanding their acoustic field of view at close range to increase the likelihood of successfully acquiring prey using echolocation, representing a case of convergent evolution of echolocation behaviour between these two taxa.
The study was funded by frame grants from the Danish Natural Science Foundation to P.T.M. and M.W., and by the National Oceanographic Partnership Programme via a research agreement between La Laguna University (N.A.d.S.) and the Woods Hole Oceanographic Institution (M.J.). F.H.J. was supported by the Danish Council for Independent Research | Natural Sciences, and is currently funded by a postdoctoral fellowship from the Carlsberg Foundation
Fri, 01 May 2015 00:00:00 GMThttp://hdl.handle.net/10023/84142015-05-01T00:00:00ZJensen, FrantsWahlberg, MagnusBeedholm, KristianJohnson, MarkAguilar de Soto, NatachaMadsen, PeterEcholocating animals exercise an extensive control over the spectral and temporal properties of their biosonar signals to facilitate perception of their actively generated auditory scene when homing in on prey. The intensity and directionality of the biosonar beam defines the field of view of echolocating animals by affecting the acoustic detection range and angular coverage. However, the spatial relationship between an echolocating predator and its prey changes rapidly, resulting in different biosonar requirements throughout prey pursuit and capture. Here, we measured single-click beam patterns using a parametric fit procedure to test whether free-ranging Atlantic spotted dolphins (Stenella frontalis) modify their biosonar beam width. We recorded echolocation clicks using a linear array of receivers and estimated the beam width of individual clicks using a parametric spectral fit, cross-validated with well-established composite beam pattern estimates. The dolphins apparently increased the biosonar beam width, to a large degree without changing the signal frequency, when they approached the recording array. This is comparable to bats that also expand their field of view during prey capture, but achieve this by decreasing biosonar frequency. This behaviour may serve to decrease the risk that rapid escape movements of prey take them outside the biosonar beam of the predator. It is likely that shared sensory requirements have resulted in bats and toothed whales expanding their acoustic field of view at close range to increase the likelihood of successfully acquiring prey using echolocation, representing a case of convergent evolution of echolocation behaviour between these two taxa.Seasonal variation in harbour seal (Phoca vitulina) blubber cortisol - A novel indicator of physiological state?http://hdl.handle.net/10023/8402
Cortisol is one of the main glucocorticoid hormones involved in both the mammalian stress response, and in fat metabolism and energy regulation, making it of increasing interest as a biomarker for stress, health and overall physiological state. However, transient stress responses to animal handling and sampling may be important sources of measurement artefact when investigating circulating concentrations of this hormone in wildlife. Here, cortisol concentrations were measured in the plasma and, for the first time, in the blubber of live captured adult harbour seals (Phoca vitulina). Plasma cortisol concentrations were positively correlated with capture time, suggesting that they were largely driven by a stress response to the capture event. In contrast, blubber cortisol concentrations were shown not to be significantly affected by capture time and varied significantly by sex and by season, with higher concentrations during natural fasting periods of their life cycle, particularly during the moult. These results suggest that cortisol may play a key role in increased fat metabolism during highly energetically demanding periods, and that blubber concentrations have the potential to be used as physiological state indicators in phocid seals.
The authors would also like to thank DRG International Inc. for their financial support that enabled the attendance of The European Cetacean Society Conference in 2012 where part of this work was presented. This work was partly supported by the National Capability Funding from the Natural Environment Research Council and by a School of Biology Class Grant.
Wed, 24 Feb 2016 00:00:00 GMThttp://hdl.handle.net/10023/84022016-02-24T00:00:00ZKershaw, Joanna L.Hall, Ailsa J.Cortisol is one of the main glucocorticoid hormones involved in both the mammalian stress response, and in fat metabolism and energy regulation, making it of increasing interest as a biomarker for stress, health and overall physiological state. However, transient stress responses to animal handling and sampling may be important sources of measurement artefact when investigating circulating concentrations of this hormone in wildlife. Here, cortisol concentrations were measured in the plasma and, for the first time, in the blubber of live captured adult harbour seals (Phoca vitulina). Plasma cortisol concentrations were positively correlated with capture time, suggesting that they were largely driven by a stress response to the capture event. In contrast, blubber cortisol concentrations were shown not to be significantly affected by capture time and varied significantly by sex and by season, with higher concentrations during natural fasting periods of their life cycle, particularly during the moult. These results suggest that cortisol may play a key role in increased fat metabolism during highly energetically demanding periods, and that blubber concentrations have the potential to be used as physiological state indicators in phocid seals.Description and seasonal detection of two potential whale calls recorded in the Indian Oceanhttp://hdl.handle.net/10023/8382
Unidentified acoustic signals are recorded by hydrophones placed in the world's oceans. Some of these sounds are suspected to originate from marine mammals. In this study, two acoustic signals recorded by two arrays at Diego Garcia in the northern Indian Ocean are described. Data were available between January 2002 and December 2003. Signals were detected manually using long-term spectral average plots. Time and frequency measurements were taken from a sample of both signals. The first unidentified signal [Diego Garcia Downsweep (DGD)] consisted of two main components. The mean frequency range of the entire signal was 19.3-45.0 Hz, with a mean duration of 36.5 s (n = 22). Detections of DGD at the northern array peaked in the austral summer, though detections at the southern array peaked during winter and spring. The second unidentified signal [Diego Garcia Croak (DGC)] consisted of one component with a mean frequency range of 16.9-49.6 Hz. The mean duration of the signal was 13.1 s (n = 10). Detections of DGC did not follow a clear seasonal pattern. These signals followed characteristics of biological sources, suggesting that they could be whale calls. Fin whale calls and possible blue whales D-calls were also identified in the data.
Tue, 01 Sep 2015 00:00:00 GMThttp://hdl.handle.net/10023/83822015-09-01T00:00:00ZSousa, Andreia GHarris, DanielleUnidentified acoustic signals are recorded by hydrophones placed in the world's oceans. Some of these sounds are suspected to originate from marine mammals. In this study, two acoustic signals recorded by two arrays at Diego Garcia in the northern Indian Ocean are described. Data were available between January 2002 and December 2003. Signals were detected manually using long-term spectral average plots. Time and frequency measurements were taken from a sample of both signals. The first unidentified signal [Diego Garcia Downsweep (DGD)] consisted of two main components. The mean frequency range of the entire signal was 19.3-45.0 Hz, with a mean duration of 36.5 s (n = 22). Detections of DGD at the northern array peaked in the austral summer, though detections at the southern array peaked during winter and spring. The second unidentified signal [Diego Garcia Croak (DGC)] consisted of one component with a mean frequency range of 16.9-49.6 Hz. The mean duration of the signal was 13.1 s (n = 10). Detections of DGC did not follow a clear seasonal pattern. These signals followed characteristics of biological sources, suggesting that they could be whale calls. Fin whale calls and possible blue whales D-calls were also identified in the data.Echolocation detections and digital video surveys provide reliable estimates of the relative density of harbour porpoiseshttp://hdl.handle.net/10023/8347
1. Robust estimates of the density or abundance of cetaceans are required to support a wide range of ecological studies and inform management decisions. Considerable effort has been put into the development of line-transect sampling techniques to obtain estimates of absolute density from aerial- and boat-based visual surveys. Surveys of cetaceans using acoustic loggers or digital cameras provide alternative methods to estimate relative density that have the potential to reduce cost and provide a verifiable record of all detections. However, the ability of these methods to provide reliable estimates of relative density has yet to be established. 2. These methodologies were compared by conducting aerial visual line-transect surveys (n = 10 days) and digital video strip-transect surveys (n = 4 days) in the Moray Firth, Scotland. Simultaneous acoustic data were collected from moored echolocation detectors (C-PODs) at 58 locations across the study site. Density surface modelling (DSM) of visual survey data was used to estimate spatial variation in relative harbour porpoise density on a 4 × 4 km grid. DSM was also performed on the digital survey data, and the resulting model output compared to that from visual survey data. Estimates of relative density from visual surveys around acoustic monitoring sites were compared with several metrics previously used to characterise variation in acoustic detections of echolocation clicks. 3. There was a strong correlation between estimates of relative density from visual surveys and digital video surveys (Spearman's ρ = 0·85). A correction to account for animals missed on the transect line [previously calculated for visual aerial surveys of harbour porpoise in the North Sea was used to convert relative density from the visual surveys to absolute density. This allowed calculation of the first estimate of a proxy for detection probability in digital video surveys, suggesting that 61% (CV = 0·53) of harbour porpoises were detected. There was also a strong correlation between acoustic detections and density with Spearman's ρ = 0·73 for detection positive hours. 4. These results provide confidence in the emerging use of digital video and acoustic surveys for studying the density of small cetaceans and their responses to environmental and anthropogenic change.
The collection of visual and acoustic data was funded by the UK Department of Energy & Climate Change, the Scottish Government, Collaborative Offshore Wind Research into the Environment (COWRIE) and Oil & Gas UK. Digital aerial surveys were funded by Moray Offshore Renewables Ltd and additional funding for analysis of the combined data sets was provided by Marine Scotland. Collaboration between the University of Aberdeen and Marine Scotland was supported by MarCRF.
Wed, 13 Jul 2016 00:00:00 GMThttp://hdl.handle.net/10023/83472016-07-13T00:00:00ZWilliamson, Laura D.Brookes, Kate L.Scott, Beth E.Graham, Isla M.Bradbury, GarethHammond, Philip S.Thompson, Paul M.1. Robust estimates of the density or abundance of cetaceans are required to support a wide range of ecological studies and inform management decisions. Considerable effort has been put into the development of line-transect sampling techniques to obtain estimates of absolute density from aerial- and boat-based visual surveys. Surveys of cetaceans using acoustic loggers or digital cameras provide alternative methods to estimate relative density that have the potential to reduce cost and provide a verifiable record of all detections. However, the ability of these methods to provide reliable estimates of relative density has yet to be established. 2. These methodologies were compared by conducting aerial visual line-transect surveys (n = 10 days) and digital video strip-transect surveys (n = 4 days) in the Moray Firth, Scotland. Simultaneous acoustic data were collected from moored echolocation detectors (C-PODs) at 58 locations across the study site. Density surface modelling (DSM) of visual survey data was used to estimate spatial variation in relative harbour porpoise density on a 4 × 4 km grid. DSM was also performed on the digital survey data, and the resulting model output compared to that from visual survey data. Estimates of relative density from visual surveys around acoustic monitoring sites were compared with several metrics previously used to characterise variation in acoustic detections of echolocation clicks. 3. There was a strong correlation between estimates of relative density from visual surveys and digital video surveys (Spearman's ρ = 0·85). A correction to account for animals missed on the transect line [previously calculated for visual aerial surveys of harbour porpoise in the North Sea was used to convert relative density from the visual surveys to absolute density. This allowed calculation of the first estimate of a proxy for detection probability in digital video surveys, suggesting that 61% (CV = 0·53) of harbour porpoises were detected. There was also a strong correlation between acoustic detections and density with Spearman's ρ = 0·73 for detection positive hours. 4. These results provide confidence in the emerging use of digital video and acoustic surveys for studying the density of small cetaceans and their responses to environmental and anthropogenic change.A 3D stereo camera system for precisely positioning animals in space and timehttp://hdl.handle.net/10023/8330
Here, we describe a portable stereo camera system that integrates a GPS receiver, an attitude sensor and 3D stereo photogrammetry to rapidly estimate the position of multiple animals in space and time. We demonstrate the performance of the system during a field test by simultaneously tracking the individual positions of six long-finned pilot whales, Globicephala melas. In shore-based accuracy trials, a system with a 50-cm stereo baseline had an average range estimation error of 0.09 m at a 5-m distance increasing up to 3.2 at 50 m. The system is especially useful in field situations where it is necessary to follow groups of animals travelling over relatively long distances and time periods whilst obtaining individual positions with high spatial and temporal resolution (up to 8 Hz). These positions provide quantitative estimates of a variety of key parameters and indicators for behavioural studies such as inter-animal distances, group dispersion, speed and heading. This system can additionally be integrated with other techniques such as archival tags, photo-identification methods or acoustic playback experiments to facilitate fieldwork investigating topics ranging from natural social behaviour to how animals respond to anthropogenic disturbance. By grounding observations in quantitative metrics, the system can characterize fine-scale behaviour or detect changes as a result of disturbance that might otherwise be difficult to observe.
PLT was supported by the Scottish Funding Council (grant HR09011) through the Marine Alliance for Science and Technology for Scotland.
Wed, 01 Apr 2015 00:00:00 GMThttp://hdl.handle.net/10023/83302015-04-01T00:00:00ZMacfarlane, NicholasHowland, JonathanJensen, FrantsTyack, Peter LloydHere, we describe a portable stereo camera system that integrates a GPS receiver, an attitude sensor and 3D stereo photogrammetry to rapidly estimate the position of multiple animals in space and time. We demonstrate the performance of the system during a field test by simultaneously tracking the individual positions of six long-finned pilot whales, Globicephala melas. In shore-based accuracy trials, a system with a 50-cm stereo baseline had an average range estimation error of 0.09 m at a 5-m distance increasing up to 3.2 at 50 m. The system is especially useful in field situations where it is necessary to follow groups of animals travelling over relatively long distances and time periods whilst obtaining individual positions with high spatial and temporal resolution (up to 8 Hz). These positions provide quantitative estimates of a variety of key parameters and indicators for behavioural studies such as inter-animal distances, group dispersion, speed and heading. This system can additionally be integrated with other techniques such as archival tags, photo-identification methods or acoustic playback experiments to facilitate fieldwork investigating topics ranging from natural social behaviour to how animals respond to anthropogenic disturbance. By grounding observations in quantitative metrics, the system can characterize fine-scale behaviour or detect changes as a result of disturbance that might otherwise be difficult to observe.Intrinsic and extrinsic drivers of activity budgets in sympatric grey and harbour sealshttp://hdl.handle.net/10023/8329
Investigation of activity budgets in relation to seasonal, intrinsic (age, sex) and extrinsic (time of day, spatial) covariates enables an understanding of how such covariates shape behavioural strategies. However, conducting such investigations in the wild is challenging, because of the required large sample size of individuals across the annual cycle, and difficulties in categorising behavioural states and analysing the resulting individual-referenced and serially correlated data. In this study, from telemetry tags deployed on 63 grey seals (Halichoerus grypus) and 126 harbour seals (Phoca vitulina) we used behavioural data, and movement data within a Bayesian state-space model (SSM), to define population-level activity budgets around Britain. Using generalised estimating equations (GEEs) we then examined how time spent in four states (resting on land (hauled out), resting at sea, foraging and travelling) was influenced by seasonal, intrinsic and extrinsic covariates. We present and discuss the following key findings. (1) We found no evidence that regional variation in foraging effort was linked to regional population trajectories in harbour seals. (2) Grey seals demonstrated sex-specific seasonal differences in their activity budgets, independent from those related to reproductive costs. (3) In these sympatric species there was evidence of temporal separation in time hauled out, but not in time foraging. (4) In both species, time spent resting at sea was separated into inshore (associated with tidal haul out availability) and offshore areas. Time spent resting at sea and on land was interchangeable to some extent, suggesting a degree of overlap in their functionality. This may result in a relaxation of the constraints associated with a central place foraging strategy. More generally, we demonstrate how a large dataset, incorporating differing tag parameters, can be analysed to define activity budgets and subsequently address important ecological questions.
D. J. F. Russell was funded by the UK Department of Energy and Climate Change (DECC) as part of their Offshore Energy Strategic Environmental Assessment programme and by Scottish Government as part of their Marine Mammal Scientific Support Research Programme (MMSS/001/11). The telemetry tags and their deployment were funded by DECC, the Natural Environment Research Council, Scottish Government, Marine Scotland Science and The European Commission.
Sun, 01 Nov 2015 00:00:00 GMThttp://hdl.handle.net/10023/83292015-11-01T00:00:00ZRussell, Deborah Jill FraserMcClintock, Brett ThomasMatthiopoulos, JasonThompson, PaulThompson, DavidHammond, Philip StevenJones, Esther LaneMacKenzie, MoniqueMoss, SimonMcConnell, Bernie JInvestigation of activity budgets in relation to seasonal, intrinsic (age, sex) and extrinsic (time of day, spatial) covariates enables an understanding of how such covariates shape behavioural strategies. However, conducting such investigations in the wild is challenging, because of the required large sample size of individuals across the annual cycle, and difficulties in categorising behavioural states and analysing the resulting individual-referenced and serially correlated data. In this study, from telemetry tags deployed on 63 grey seals (Halichoerus grypus) and 126 harbour seals (Phoca vitulina) we used behavioural data, and movement data within a Bayesian state-space model (SSM), to define population-level activity budgets around Britain. Using generalised estimating equations (GEEs) we then examined how time spent in four states (resting on land (hauled out), resting at sea, foraging and travelling) was influenced by seasonal, intrinsic and extrinsic covariates. We present and discuss the following key findings. (1) We found no evidence that regional variation in foraging effort was linked to regional population trajectories in harbour seals. (2) Grey seals demonstrated sex-specific seasonal differences in their activity budgets, independent from those related to reproductive costs. (3) In these sympatric species there was evidence of temporal separation in time hauled out, but not in time foraging. (4) In both species, time spent resting at sea was separated into inshore (associated with tidal haul out availability) and offshore areas. Time spent resting at sea and on land was interchangeable to some extent, suggesting a degree of overlap in their functionality. This may result in a relaxation of the constraints associated with a central place foraging strategy. More generally, we demonstrate how a large dataset, incorporating differing tag parameters, can be analysed to define activity budgets and subsequently address important ecological questions.How effectively do horizontal and vertical response strategies of long-finned pilot whales reduce sound exposure from naval sonar?http://hdl.handle.net/10023/8288
The behaviour of a marine mammal near a noise source can modulate the sound exposure it receives. We demonstrate that two long-finned pilot whales both surfaced in synchrony with consecutive arrivals of multiple sonar pulses. We then assess the effect of surfacing and other behavioural response strategies on the received cumulative sound exposure levels and maximum sound pressure levels (SPLs) by modelling realistic spatiotemporal interactions of a pilot whale with an approaching source. Under the propagation conditions of our model, some response strategies observed in the wild were effective in reducing received levels (e.g. movement perpendicular to the source's line of approach), but others were not (e.g. switching from deep to shallow diving; synchronous surfacing after maximum SPLs). Our study exemplifies how simulations of source-whale interactions guided by detailed observational data can improve our understanding about motivations behind behaviour responses observed in the wild (e.g., reducing sound exposure, prey movement).
PJW was supported with studentships of The Netherlands Ministry of Defence (grant number 032.30370/01.02) and the VSB Foundation (grant number VSB.08/228-E) and Ren e Dekeling is acknowledged for making funding possible. The 3S project was supported by the US Ofﬁce of Naval Research, The Netherlands Ministry of Defence, Royal Norwegian Navy and Norwegian Ministry of Defence, and by World Wildlife Fund Norway. PLT received funding from the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland) and their support is gratefully acknowledged.
Fri, 01 May 2015 00:00:00 GMThttp://hdl.handle.net/10023/82882015-05-01T00:00:00ZWensveen, Paulus Jacobusvon Benda-Beckmann, Alexander MAinslie, Michael ALam, Frans-Peter AKvadsheim, Petter HTyack, Peter LMiller, Patrick J OThe behaviour of a marine mammal near a noise source can modulate the sound exposure it receives. We demonstrate that two long-finned pilot whales both surfaced in synchrony with consecutive arrivals of multiple sonar pulses. We then assess the effect of surfacing and other behavioural response strategies on the received cumulative sound exposure levels and maximum sound pressure levels (SPLs) by modelling realistic spatiotemporal interactions of a pilot whale with an approaching source. Under the propagation conditions of our model, some response strategies observed in the wild were effective in reducing received levels (e.g. movement perpendicular to the source's line of approach), but others were not (e.g. switching from deep to shallow diving; synchronous surfacing after maximum SPLs). Our study exemplifies how simulations of source-whale interactions guided by detailed observational data can improve our understanding about motivations behind behaviour responses observed in the wild (e.g., reducing sound exposure, prey movement).Sperm whale echolocation behaviour reveals a directed, prior-based search strategy informed by prey distributionhttp://hdl.handle.net/10023/8168
Predators make foraging decisions based upon sensory information about resource availability, but little is known about how large, air-breathing predators collect and use such information to maximize energy returns when foraging in the deep sea. Here, we used archival tags to study how echolocating sperm whales (Physeter macrocephalus) use their long-range sensory capabilities to guide foraging in a deep-water habitat consisting of multiple, depth-segregated prey layers. Sperm whales employ a directed search behaviour by modulating their overall sonar sampling with the intention to exploit a particular prey layer. They forage opportunistically during some descents while actively adjusting their acoustic gaze to sequentially track different prey layers. While foraging within patches, sperm whales adjust their clicking rate both to search new water volumes as they turn and to match the prey distribution. This strategy increases information flow and suggests that sperm whales can perform auditory stream segregation of multiple targets when echolocating. Such flexibility in sampling tactics in concert with long-range sensing capabilities apparently allow sperm whales to efficiently locate and access prey resources in vast, heterogeneous, deep water habitats.
The fieldwork was funded by a grant from the Carlsberg Foundation to B. Møhl and ONR, SERDP and FNU grants to MJ, PJOM and PTM. PJOM was supported by a Royal Society Fellowship, NAS by the International Campus of Excellence of the Canary Islands, MJ by the Marine Alliance for Science and Technology for Scotland and AF partly by project CETOBAPH (grant number CGL2009-1311218).
Wed, 01 Apr 2015 00:00:00 GMThttp://hdl.handle.net/10023/81682015-04-01T00:00:00ZFais, A.Aguilar de Soto, NatachaJohnson, M.Pérez-González, C.Miller, P.J.O.Madsen, P.T.Predators make foraging decisions based upon sensory information about resource availability, but little is known about how large, air-breathing predators collect and use such information to maximize energy returns when foraging in the deep sea. Here, we used archival tags to study how echolocating sperm whales (Physeter macrocephalus) use their long-range sensory capabilities to guide foraging in a deep-water habitat consisting of multiple, depth-segregated prey layers. Sperm whales employ a directed search behaviour by modulating their overall sonar sampling with the intention to exploit a particular prey layer. They forage opportunistically during some descents while actively adjusting their acoustic gaze to sequentially track different prey layers. While foraging within patches, sperm whales adjust their clicking rate both to search new water volumes as they turn and to match the prey distribution. This strategy increases information flow and suggests that sperm whales can perform auditory stream segregation of multiple targets when echolocating. Such flexibility in sampling tactics in concert with long-range sensing capabilities apparently allow sperm whales to efficiently locate and access prey resources in vast, heterogeneous, deep water habitats.The evolutionary roots of creativity : mechanisms and motivationshttp://hdl.handle.net/10023/8111
We consider the evolution of cognition and the emergence of creative behaviour, in relation to vocal communication. We address two key questions: (i) what cognitive and/or social mechanisms have evolved that afford aspects of creativity?; (ii) has natural and/or sexual selection favoured human behaviours considered ‘creative’? This entails analysis of ‘creativity’, an imprecise construct: comparable properties in non-humans differ in magnitude and teleology from generally agreed human creativity. We then address two apparent problems: (i) the difference between merely novel productions and ‘creative’ ones; (ii) the emergence of creative behaviour in spite of high cost: does it fit the idea that females choose a male who succeeds in spite of a handicap (costly ornament); or that creative males capable of producing a large and complex song repertoire grew up under favourable conditions; or a demonstration of generally beneficial heightened reasoning capacity; or an opportunity to continually reinforce social bonding through changing communication tropes; or something else? We illustrate and support our argument by reference to whale and bird song; these independently evolved biological signal mechanisms objectively share surface properties with human behaviours generally called ‘creative’. Studying them may elucidate mechanisms underlying human creativity; we outline a research programme to do so.
Funding: MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland). MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions.
Sun, 01 Mar 2015 00:00:00 GMThttp://hdl.handle.net/10023/81112015-03-01T00:00:00ZWiggins, Geraint A.Tyack, Peter LloydScharff, ConstanceRohrmeier, MartinWe consider the evolution of cognition and the emergence of creative behaviour, in relation to vocal communication. We address two key questions: (i) what cognitive and/or social mechanisms have evolved that afford aspects of creativity?; (ii) has natural and/or sexual selection favoured human behaviours considered ‘creative’? This entails analysis of ‘creativity’, an imprecise construct: comparable properties in non-humans differ in magnitude and teleology from generally agreed human creativity. We then address two apparent problems: (i) the difference between merely novel productions and ‘creative’ ones; (ii) the emergence of creative behaviour in spite of high cost: does it fit the idea that females choose a male who succeeds in spite of a handicap (costly ornament); or that creative males capable of producing a large and complex song repertoire grew up under favourable conditions; or a demonstration of generally beneficial heightened reasoning capacity; or an opportunity to continually reinforce social bonding through changing communication tropes; or something else? We illustrate and support our argument by reference to whale and bird song; these independently evolved biological signal mechanisms objectively share surface properties with human behaviours generally called ‘creative’. Studying them may elucidate mechanisms underlying human creativity; we outline a research programme to do so.Individual, unit and vocal clan level identity cues in sperm whale codashttp://hdl.handle.net/10023/8071
The ‘social complexity hypothesis’ suggests that complex social structure is a driver of diversity in animal communication systems. Sperm whales have a hierarchically structured society in which the largest affiliative structures, the vocal clans, are marked on ocean-basin scales by culturally transmitted dialects of acoustic signals known as ‘codas’. We examined variation in coda repertoires among both individual whales and social units—the basic element of sperm whale society—using data from nine Caribbean social units across six years. Codas were assigned to individuals using photo-identification and acoustic size measurement, and we calculated similarity between repertoires using both continuous and categorical methods. We identified 21 coda types. Two of those (‘1+1+3’ and ‘5R1’) made up 65% of the codas recorded, were shared across all units and have dominated repertoires in this population for at least 30 years. Individuals appear to differ in the way they produce ‘5R1’ but not ‘1+1+3’ coda. Units use distinct 4-click coda types which contribute to making unit repertoires distinctive. Our results support the social complexity hypothesis in a marine species as different patterns of variation between coda types suggest divergent functions, perhaps representing selection for identity signals at several levels of social structure.
Fieldwork was supported by Discovery and Equipment grants to H.W. from the Natural Sciences and Engineering Research Council of Canada (NSERC) and the Whale and Dolphin Conservation Society. S.G. and L.R. were supported by the Marine Alliance for Science and Technology for Scotland (MASTs) pooling initiative and their support is gratefully acknowledged. MASTs is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions. S.G. was also supported by an NSERC Postgraduate Scholarship (PGS-M), an NSERC Canadian Graduate Scholarship (CGS-D), the Izaak Killam Memorial Scholarship, the Patrick F. Lett Fund, the Dalhousie’s Presidents Award, and an FNU fellowship for the Danish Council for Independent Research from the Ministry of Higher Education and Science supplemented by a Sapere Aude Research Talent Award.
Wed, 20 Jan 2016 00:00:00 GMThttp://hdl.handle.net/10023/80712016-01-20T00:00:00ZGero, ShaneWhitehead, HalRendell, LukeThe ‘social complexity hypothesis’ suggests that complex social structure is a driver of diversity in animal communication systems. Sperm whales have a hierarchically structured society in which the largest affiliative structures, the vocal clans, are marked on ocean-basin scales by culturally transmitted dialects of acoustic signals known as ‘codas’. We examined variation in coda repertoires among both individual whales and social units—the basic element of sperm whale society—using data from nine Caribbean social units across six years. Codas were assigned to individuals using photo-identification and acoustic size measurement, and we calculated similarity between repertoires using both continuous and categorical methods. We identified 21 coda types. Two of those (‘1+1+3’ and ‘5R1’) made up 65% of the codas recorded, were shared across all units and have dominated repertoires in this population for at least 30 years. Individuals appear to differ in the way they produce ‘5R1’ but not ‘1+1+3’ coda. Units use distinct 4-click coda types which contribute to making unit repertoires distinctive. Our results support the social complexity hypothesis in a marine species as different patterns of variation between coda types suggest divergent functions, perhaps representing selection for identity signals at several levels of social structure.A single-station method for the detection, classification and location of fin whale calls using ocean-bottom seismic stationshttp://hdl.handle.net/10023/8064
Passive seismic monitoring in the oceans uses long-term deployments of Ocean Bottom Seismometers (OBSs). An OBS usually records the three components of ground motion and pressure, typically at 100Hz. This makes the OBS an ideal tool to investigate fin and blue whales that vocalize at frequencies below 45Hz. Previous applications of OBS data to locate whale calls have relied on single channel analyses that disregard the information that is conveyed by the horizontal seismic channels. Recently, Harris, Matias, Thomas, Harwood, and Geissler [J. Acoust. Soc. Am. 134, 3522-3535 (2013)] presented a method that used all four channels recorded by one OBS to derive the range and azimuth of fin whale calls. In this work, the detection, classification, and ranging of calls using this four-channel method were further investigated, focusing on methods to increase the accuracy of range estimates to direct path arrivals. Corrections to account for the influences of the sound speed in the water layer and the velocity structure in the top strata of the seabed were considered. The single station method discussed here is best implemented when OBSs have been deployed in deep water on top of seabed strata with low P-wave velocity. These conditions maximize the ability to detect and estimate ranges to fin whale calls.
Wed, 01 Jul 2015 00:00:00 GMThttp://hdl.handle.net/10023/80642015-07-01T00:00:00ZMatias, L.Harris, D.Passive seismic monitoring in the oceans uses long-term deployments of Ocean Bottom Seismometers (OBSs). An OBS usually records the three components of ground motion and pressure, typically at 100Hz. This makes the OBS an ideal tool to investigate fin and blue whales that vocalize at frequencies below 45Hz. Previous applications of OBS data to locate whale calls have relied on single channel analyses that disregard the information that is conveyed by the horizontal seismic channels. Recently, Harris, Matias, Thomas, Harwood, and Geissler [J. Acoust. Soc. Am. 134, 3522-3535 (2013)] presented a method that used all four channels recorded by one OBS to derive the range and azimuth of fin whale calls. In this work, the detection, classification, and ranging of calls using this four-channel method were further investigated, focusing on methods to increase the accuracy of range estimates to direct path arrivals. Corrections to account for the influences of the sound speed in the water layer and the velocity structure in the top strata of the seabed were considered. The single station method discussed here is best implemented when OBSs have been deployed in deep water on top of seabed strata with low P-wave velocity. These conditions maximize the ability to detect and estimate ranges to fin whale calls.Maternal oxytocin is linked to close mother-infant proximity in grey seals (Halichoerus grypus)http://hdl.handle.net/10023/8012
Maternal behaviour is a crucial component of reproduction in all mammals; however the quality of care that mothers give to infants can vary greatly. It is vital to document variation in maternal behaviour caused by the physiological processes controlling its expression. This underlying physiology should be conserved throughout reproductive events and should be replicated across all individuals of a species; therefore, any correlates to maternal care quality may be present across many individuals or contexts. Oxytocin modulates the initiation and expression of maternal behaviour in mammals; therefore we tested whether maternal plasma oxytocin concentrations correlated to key maternal behaviours in wild grey seals (Halichoerus grypus). Plasma oxytocin concentrations in non-breeding individuals (4.3 ±0.5 pg/ml) were significantly lower than those in mothers with dependent pups in both early (8.2 ±0.8 37 pg/ml) and late (6.9 ±0.7 pg/ml) lactation. Maternal plasma oxytocin concentrations were not correlated to the amount of nursing prior to sampling, or a mother’s nursing intensity throughout the dependant period. Mothers with high plasma oxytocin concentrations stayed closer to their pups, reducing the likelihood of mother-pup separation during lactation which is credited with causing starvation, the largest cause of pup mortality in grey seals. This is the first study to link endogenous oxytocin concentrations in wild mammalian mothers with any type of maternal behaviour. Oxytocin’s structure and function is widely conserved across mammalian mothers, including humans. Defining the impact the oxytocin system has on maternal behaviour highlights relationships that may occur across many individuals or species, and such behaviours heavily influence infant development and an individual’s lifetime reproductive success.
The UK’s Natural Environmental Research Council (http://www.nerc.ac.uk/) funded the long term program of research on grey seals at North Rona andthe Isle of May. PPP and SDT were in receipt of NERC grant NE/G008930/1 during the work. This paper formed part of KJR’s PhD funded by the UK Natural Environment Research Council grant NE/H524930/1 and by SMRU Marine (http://www.smru. st-andrews.ac.uk/), St Andrews, UK.
Wed, 23 Dec 2015 00:00:00 GMThttp://hdl.handle.net/10023/80122015-12-23T00:00:00ZRobinson, Kelly JoanneTwiss, Sean D.Hazon, NeilPomeroy, PatrickMaternal behaviour is a crucial component of reproduction in all mammals; however the quality of care that mothers give to infants can vary greatly. It is vital to document variation in maternal behaviour caused by the physiological processes controlling its expression. This underlying physiology should be conserved throughout reproductive events and should be replicated across all individuals of a species; therefore, any correlates to maternal care quality may be present across many individuals or contexts. Oxytocin modulates the initiation and expression of maternal behaviour in mammals; therefore we tested whether maternal plasma oxytocin concentrations correlated to key maternal behaviours in wild grey seals (Halichoerus grypus). Plasma oxytocin concentrations in non-breeding individuals (4.3 ±0.5 pg/ml) were significantly lower than those in mothers with dependent pups in both early (8.2 ±0.8 37 pg/ml) and late (6.9 ±0.7 pg/ml) lactation. Maternal plasma oxytocin concentrations were not correlated to the amount of nursing prior to sampling, or a mother’s nursing intensity throughout the dependant period. Mothers with high plasma oxytocin concentrations stayed closer to their pups, reducing the likelihood of mother-pup separation during lactation which is credited with causing starvation, the largest cause of pup mortality in grey seals. This is the first study to link endogenous oxytocin concentrations in wild mammalian mothers with any type of maternal behaviour. Oxytocin’s structure and function is widely conserved across mammalian mothers, including humans. Defining the impact the oxytocin system has on maternal behaviour highlights relationships that may occur across many individuals or species, and such behaviours heavily influence infant development and an individual’s lifetime reproductive success.Efficient abstracting of dive profiles using a broken-stick modelhttp://hdl.handle.net/10023/7972
For diving animals, animal-borne sensors are used to collect time-depth information for studying behaviour, ranging patterns and foraging ecology. Often, this information needs to be compressed for storage or transmission. Widely used devices called conductivity-temperature-depth satellite relay data loggers (CTD-SRDLs) sample time and depth at high resolution during a dive and then abstract the time-depth trajectory using a broken-stick model (BSM). This approximation method can summarize efficiently the curvilinear shape of a dive, using a piecewise linear shape with a small, fixed number of vertices, or break points. We present the process of abstracting dives using the BSM and quantify its performance, by measuring the uncertainty associated with the profiles it produces. We develop a method for obtaining a confidence zone and an index for the goodness-of-fit (dive zone index, DZI) for abstracted dive profiles. We validate our results with a case study using dives from elephant seals (Mirounga spp.). We use generalized additive models (GAMs) to determine whether the DZI can be used as a proxy for an absolute measure of fit and investigate the relationship between the DZI and the dive shape. We found a strong correlation between the residual sum of squares (RSS) for the difference between the detailed and abstracted profiles, and the DZI and maximum residual (R4), for dives resulting from CTD-SRDLs (69% deviance explained). On its own, the DZI explained a lower percentage of deviance which was variable for abstracted dives with different numbers of break points. We also found evidence for systematic differences in the DZI for different dive shapes (65% deviance explained). Although the proportional loss of information in the abstraction of time-depth dive profiles by BSM is high, what remains is sufficient to infer goodness-of-fit of the abstracted profile by reversing the abstraction process. Our results suggest that together the DZI and R4 can be used as a proxy for the RSS, and we present the method for obtaining these metrics for BSM-abstracted profiles.
This work was supported by SMRU Ltd (now SMRU Marine) in the form of a PhD fellowship (T.P.). Completion of the manuscript was supported by a National Research Foundation Scarce Skills Postdoctoral Fellowship at the University of Cape Town, South Africa (T.P.). The CTD-SRDL data presented in this manuscript were collected as part of a project funded by the Natural Environment Research Council (NERC) grants NE/E018289/1 and NER/D/S/2002/00426.
Sun, 01 Mar 2015 00:00:00 GMThttp://hdl.handle.net/10023/79722015-03-01T00:00:00ZPhotopoulou, T.Lovell, PhilipFedak, M.A.Thomas, L.Matthiopoulos, J.For diving animals, animal-borne sensors are used to collect time-depth information for studying behaviour, ranging patterns and foraging ecology. Often, this information needs to be compressed for storage or transmission. Widely used devices called conductivity-temperature-depth satellite relay data loggers (CTD-SRDLs) sample time and depth at high resolution during a dive and then abstract the time-depth trajectory using a broken-stick model (BSM). This approximation method can summarize efficiently the curvilinear shape of a dive, using a piecewise linear shape with a small, fixed number of vertices, or break points. We present the process of abstracting dives using the BSM and quantify its performance, by measuring the uncertainty associated with the profiles it produces. We develop a method for obtaining a confidence zone and an index for the goodness-of-fit (dive zone index, DZI) for abstracted dive profiles. We validate our results with a case study using dives from elephant seals (Mirounga spp.). We use generalized additive models (GAMs) to determine whether the DZI can be used as a proxy for an absolute measure of fit and investigate the relationship between the DZI and the dive shape. We found a strong correlation between the residual sum of squares (RSS) for the difference between the detailed and abstracted profiles, and the DZI and maximum residual (R4), for dives resulting from CTD-SRDLs (69% deviance explained). On its own, the DZI explained a lower percentage of deviance which was variable for abstracted dives with different numbers of break points. We also found evidence for systematic differences in the DZI for different dive shapes (65% deviance explained). Although the proportional loss of information in the abstraction of time-depth dive profiles by BSM is high, what remains is sufficient to infer goodness-of-fit of the abstracted profile by reversing the abstraction process. Our results suggest that together the DZI and R4 can be used as a proxy for the RSS, and we present the method for obtaining these metrics for BSM-abstracted profiles.Evidence of land-sea transfer of the zoonotic pathogen Campylobacter to a wildlife marine sentinel specieshttp://hdl.handle.net/10023/7956
Environmental pollution often accompanies the expansion and urbanization of human populations where sewage and wastewaters commonly have an impact on the marine environments. Here, we explored the potential for faecal bacterial pathogens, of anthropic origin, to spread to marine wildlife in coastal areas. The common zoonotic bacterium Campylobacter was isolated from grey seals (Halichoerus grypus), an important sentinel species for environmental pollution, and compared to isolates from wild birds, agricultural sources and clinical samples to characterize possible transmission routes. Campylobacter jejuni was present in half of all grey seal pups sampled (24/50 dead and 46/90 live pups) in the breeding colony on the Isle of May (Scotland), where it was frequently associated with histological evidence of disease. Returning yearling animals (19/19) were negative for C. jejuni suggesting clearance of infection while away from the localized colony infection source. The genomes of 90 isolates from seals were sequenced and characterized using a whole-genome multilocus sequence typing (MLST) approach and compared to 192 published genomes from multiple sources using population genetic approaches and a probabilistic genetic attribution model to infer the source of infection from MLST data. The strong genotype-host association has enabled the application of source attribution models in epidemiological studies of human campylobacteriosis, and here assignment analyses consistently grouped seal isolates with those from human clinical samples. These findings are consistent with either a common infection source or direct transmission of human campylobacter to grey seals, raising concerns about the spread of human pathogens to wildlife marine sentinel species in coastal areas.
This work and JLB's PhD studentship were funded by the Moredun Research Institute and the Royal Zoological Society of Scotland. SKS is funded by the Biotechnology and Biological Sciences Research Council (BBSRC), the Medical Research Council (MR/L015080/1) and the Wellcome Trust. Date of Acceptance: 13/11/2014
Thu, 01 Jan 2015 00:00:00 GMThttp://hdl.handle.net/10023/79562015-01-01T00:00:00ZBaily, J.L.Méric, G.Bayliss, S.Foster, G.Moss, S.E.Watson, E.Pascoe, B.Mikhail, J.Pizzi, R.Goldstone, R.J.Smith, D.G.E.Willoughby, K.Hall, A.J.Sheppard, S.K.Dagleish, M.P.Environmental pollution often accompanies the expansion and urbanization of human populations where sewage and wastewaters commonly have an impact on the marine environments. Here, we explored the potential for faecal bacterial pathogens, of anthropic origin, to spread to marine wildlife in coastal areas. The common zoonotic bacterium Campylobacter was isolated from grey seals (Halichoerus grypus), an important sentinel species for environmental pollution, and compared to isolates from wild birds, agricultural sources and clinical samples to characterize possible transmission routes. Campylobacter jejuni was present in half of all grey seal pups sampled (24/50 dead and 46/90 live pups) in the breeding colony on the Isle of May (Scotland), where it was frequently associated with histological evidence of disease. Returning yearling animals (19/19) were negative for C. jejuni suggesting clearance of infection while away from the localized colony infection source. The genomes of 90 isolates from seals were sequenced and characterized using a whole-genome multilocus sequence typing (MLST) approach and compared to 192 published genomes from multiple sources using population genetic approaches and a probabilistic genetic attribution model to infer the source of infection from MLST data. The strong genotype-host association has enabled the application of source attribution models in epidemiological studies of human campylobacteriosis, and here assignment analyses consistently grouped seal isolates with those from human clinical samples. These findings are consistent with either a common infection source or direct transmission of human campylobacter to grey seals, raising concerns about the spread of human pathogens to wildlife marine sentinel species in coastal areas.Fishing for drifts : detecting buoyancy changes of a top marine predator using a step-wise filtering methodhttp://hdl.handle.net/10023/7923
In southern elephant seals (Mirounga leonina), fasting and foraging related fluctuations in body composition are reflected by buoyancy changes which can be monitored by changes in drift rate. Here, we present an improved knowledge-based method for detecting buoyancy changes from compressed and abstracted dive profiles received through telemetry. We applied this step-wise filtering method to the dive records of 11 southern elephant seals, which identified 0.8% to 2.2% of all dives as drift dives. At the beginning of the migration, all individuals were strongly negatively buoyant. Over the following 75 to 150 days, the buoyancy reached a peak close to or at neutral buoyancy, indicative of a seal’s foraging success. Ground-truthing confirmed that this new knowledge-based method is capable to reliably detect buoyancy changes in the dive records of drift diving species using abstracted dive profiles. This affirms that the abstraction algorithm conveys sufficient detail of the geometric shape of drift dives for them to be identified. It also suggest that using this step-wise filtering method, buoyancy changes could be detected even in old datasets with compressed dive information, for which conventional drift dive classification previously failed.
This research was partly funded by a Natural Environment Research Council grant [NE/E018289/1]. Further, a PhD studentship in Marine Biology partially funded by the Natural Environment Research Council [NE/L501852/1] and the University of St Andrews 600th Scholarship supported this work.
Wed, 02 Dec 2015 00:00:00 GMThttp://hdl.handle.net/10023/79232015-12-02T00:00:00ZGordine, Samantha AlexFedak, MikeBoehme, LarsIn southern elephant seals (Mirounga leonina), fasting and foraging related fluctuations in body composition are reflected by buoyancy changes which can be monitored by changes in drift rate. Here, we present an improved knowledge-based method for detecting buoyancy changes from compressed and abstracted dive profiles received through telemetry. We applied this step-wise filtering method to the dive records of 11 southern elephant seals, which identified 0.8% to 2.2% of all dives as drift dives. At the beginning of the migration, all individuals were strongly negatively buoyant. Over the following 75 to 150 days, the buoyancy reached a peak close to or at neutral buoyancy, indicative of a seal’s foraging success. Ground-truthing confirmed that this new knowledge-based method is capable to reliably detect buoyancy changes in the dive records of drift diving species using abstracted dive profiles. This affirms that the abstraction algorithm conveys sufficient detail of the geometric shape of drift dives for them to be identified. It also suggest that using this step-wise filtering method, buoyancy changes could be detected even in old datasets with compressed dive information, for which conventional drift dive classification previously failed.Non-song social call bouts of migrating humpback whaleshttp://hdl.handle.net/10023/7875
The use of stereotyped calls within structured bouts has been described for a number of species and may increase the information potential of call repertoires. Humpback whales produce a repertoire of social calls, although little is known about the complexity or function of these calls. In this study, digital acoustic tag recordings were used to investigate social call use within bouts, the use of bouts across different social contexts, and whether particular call type combinations were favored. Call order within bouts was investigated using call transition frequencies and information theory techni- ques. Call bouts were defined through analysis of inter-call intervals, as any calls within 3.9 s of each other. Bouts were produced significantly more when new whales joined a group compared to groups that did not change membership, and in groups containing multiple adults escorting a female and calf compared to adult only groups. Although social calls tended to be produced in bouts, there were few repeated bout types. However, the order in which most call types were produced within bouts was non-random and dependent on the preceding call type. These bouts appear to be at least partially governed by rules for how individual components are combined.
This work was funded by the E&P Sound and Marine Life Joint Industry Programme (JIP), managed by the International Association of Oil and Gas Producers (OGP), the U.S. Bureau of Ocean Energy Management (BOEM), and the U.S. Office of Naval Research (ONR) with additional in-kind support from the Australian Defence Science and Technology Organisation.
Mon, 01 Jun 2015 00:00:00 GMThttp://hdl.handle.net/10023/78752015-06-01T00:00:00ZRekdahl, MelindaDunlop, RebeccaGoldizen, AnneGarland, Ellen ClareBiassoni, NicolettaMiller, PatrickNoad, MichaelThe use of stereotyped calls within structured bouts has been described for a number of species and may increase the information potential of call repertoires. Humpback whales produce a repertoire of social calls, although little is known about the complexity or function of these calls. In this study, digital acoustic tag recordings were used to investigate social call use within bouts, the use of bouts across different social contexts, and whether particular call type combinations were favored. Call order within bouts was investigated using call transition frequencies and information theory techni- ques. Call bouts were defined through analysis of inter-call intervals, as any calls within 3.9 s of each other. Bouts were produced significantly more when new whales joined a group compared to groups that did not change membership, and in groups containing multiple adults escorting a female and calf compared to adult only groups. Although social calls tended to be produced in bouts, there were few repeated bout types. However, the order in which most call types were produced within bouts was non-random and dependent on the preceding call type. These bouts appear to be at least partially governed by rules for how individual components are combined.Beluga whale (Delphinapterus leucas) vocalizations and call classification from the eastern Beaufort Sea populationhttp://hdl.handle.net/10023/7874
Beluga whales, Delphinapterus leucas, have a graded call system; call types exist on a continuum making classification challenging. A description of vocalizations from the eastern Beaufort Sea beluga population during its spring migration are presented here, using both a non-parametric clas- sification tree analysis (CART), and a Random Forest analysis. Twelve frequency and duration measurements were made on 1019 calls recorded over 14 days off Icy Cape, Alaska, resulting in 34 identifiable call types with 83% agreement in classification for both CART and Random Forest analyses. This high level of agreement in classification, with an initial subjective classification of calls into 36 categories, demonstrates that the methods applied here provide a quantitative analysis of a graded call dataset. Further, as calls cannot be attributed to individuals using single sensor pas- sive acoustic monitoring efforts, these methods provide a comprehensive analysis of data where the influence of pseudo-replication of calls from individuals is unknown. This study is the first to describe the vocal repertoire of a beluga population using a robust and repeatable methodology. A baseline eastern Beaufort Sea beluga population repertoire is presented here, against which the call repertoire of other seasonally sympatric Alaskan beluga populations can be compared.
Funding was provided by the Bureau of Ocean Energy Management under InterAgency Agreement M09PG00016. E.C.G. was supported by a National Research Council (National Academy of Sciences) Postdoctoral Fellowship.
Mon, 01 Jun 2015 00:00:00 GMThttp://hdl.handle.net/10023/78742015-06-01T00:00:00ZGarland, Ellen ClareCastellote, ManuelBerchok, CatherineBeluga whales, Delphinapterus leucas, have a graded call system; call types exist on a continuum making classification challenging. A description of vocalizations from the eastern Beaufort Sea beluga population during its spring migration are presented here, using both a non-parametric clas- sification tree analysis (CART), and a Random Forest analysis. Twelve frequency and duration measurements were made on 1019 calls recorded over 14 days off Icy Cape, Alaska, resulting in 34 identifiable call types with 83% agreement in classification for both CART and Random Forest analyses. This high level of agreement in classification, with an initial subjective classification of calls into 36 categories, demonstrates that the methods applied here provide a quantitative analysis of a graded call dataset. Further, as calls cannot be attributed to individuals using single sensor pas- sive acoustic monitoring efforts, these methods provide a comprehensive analysis of data where the influence of pseudo-replication of calls from individuals is unknown. This study is the first to describe the vocal repertoire of a beluga population using a robust and repeatable methodology. A baseline eastern Beaufort Sea beluga population repertoire is presented here, against which the call repertoire of other seasonally sympatric Alaskan beluga populations can be compared.Acoustic sequences in non-human animals : a tutorial review and prospectushttp://hdl.handle.net/10023/7848
Animal acoustic communication often takes the form of complex sequences, made up of multiple distinct acoustic units. Apart from the well-known example of birdsong, other animals such as insects, amphibians,and mammals (including bats, rodents, primates, and cetaceans) also generate complex acoustic sequences. Occasionally, such as with birdsong, the adaptive role of these sequences seems clear (e.g. mate attraction and territorial defence). More often however, researchers have only begun to characterise – let alone understand – the significance and meaning of acoustic sequences. Hypotheses abound, but there is little agreement as to how sequences should be defined and analysed. Our review aims to outline suitable methods for testing these hypotheses, and to describe the major limitations to our current and near-future knowledge on questions of acoustic sequences. This review and prospectus is the result of a collaborative effort between 43 scientists from the fields of animal behaviour, ecology and evolution, signal processing, machine learning,quantitative linguistics, and information theory, who gathered for a 2013 workshop entitled, ‘Analysing vocal sequences in animals’. Our goal is to present not just a review of the state of the art, but to propose a methodological framework that summarises what we suggest are the best practices for research in this field,across taxa and across disciplines. We also provide a tutorial-style introduction to some of the most promising algorithmic approaches for analysing sequences. We divide our review into three sections: identifying the distinct units of an acoustic sequence, describing the different ways that information can be contained within a sequence, and analysing the structure of that sequence. Each of these sections is further subdivided to address the key questions and approaches in that area. We propose a uniform, systematic, and comprehensive approach to studying sequences, with the goal of clarifying research terms used in different fields, and facilitating collaboration and comparative studies. Allowing greater interdisciplinary collaboration will facilitate the investigation of many important questions in the evolution of communication and sociality.
Mon, 01 Feb 2016 00:00:00 GMThttp://hdl.handle.net/10023/78482016-02-01T00:00:00ZKershenbaum, ArikBlumstein, DanRoch, MarieAkçay, ÇaglarBackus, GregoryBee, Mark A.Bohn, KirstenCao, YanCarter, GeraldCäsar, CristianeCoen, MichaelDe Ruiter, Stacy LynnDoyle, LauranceEdelman, ShimonFerrer-i-Cancho, RamonFreeberg, Todd M.Garland, Ellen ClareGustison, MorganHarley, Heidi E.Huetz, ChloéHughes, MelissaBruno, Julia HylandIlany, AmiyaalJin, Dezhe Z.Johnson, MichaelJu, ChenghuiKarnowski, JeremyLohr, BernardManser, MartaMcCowan, BrendaMercado III, EduardoNarins, Peter M.Piel, AlexRice, MeganSalmi, RobertaSasahara, KazutoshiSayigh, LaelaShiu, YuTaylor, CharlesVallejo, Edgar E.Waller, SaraZamora-Gutierrez, VeronicaAnimal acoustic communication often takes the form of complex sequences, made up of multiple distinct acoustic units. Apart from the well-known example of birdsong, other animals such as insects, amphibians,and mammals (including bats, rodents, primates, and cetaceans) also generate complex acoustic sequences. Occasionally, such as with birdsong, the adaptive role of these sequences seems clear (e.g. mate attraction and territorial defence). More often however, researchers have only begun to characterise – let alone understand – the significance and meaning of acoustic sequences. Hypotheses abound, but there is little agreement as to how sequences should be defined and analysed. Our review aims to outline suitable methods for testing these hypotheses, and to describe the major limitations to our current and near-future knowledge on questions of acoustic sequences. This review and prospectus is the result of a collaborative effort between 43 scientists from the fields of animal behaviour, ecology and evolution, signal processing, machine learning,quantitative linguistics, and information theory, who gathered for a 2013 workshop entitled, ‘Analysing vocal sequences in animals’. Our goal is to present not just a review of the state of the art, but to propose a methodological framework that summarises what we suggest are the best practices for research in this field,across taxa and across disciplines. We also provide a tutorial-style introduction to some of the most promising algorithmic approaches for analysing sequences. We divide our review into three sections: identifying the distinct units of an acoustic sequence, describing the different ways that information can be contained within a sequence, and analysing the structure of that sequence. Each of these sections is further subdivided to address the key questions and approaches in that area. We propose a uniform, systematic, and comprehensive approach to studying sequences, with the goal of clarifying research terms used in different fields, and facilitating collaboration and comparative studies. Allowing greater interdisciplinary collaboration will facilitate the investigation of many important questions in the evolution of communication and sociality.Dose response severity functions for acoustic disturbance in cetaceans using recurrent event survival analysishttp://hdl.handle.net/10023/7845
Behavioral response studies (BRSs) aim to enhance our understanding of the behavior changes made by animals in response to specific exposure levels of different stimuli, often presented in an increasing dosage. Here, we focus on BRSs that aim to understand behavioral responses of free-ranging whales and dolphins to manmade acoustic signals (although the methods are applicable more generally). One desired outcome of these studies is dose-response functions relevant to different species, signals and contexts. We adapted and applied recurrent event survival analysis (Cox proportional hazard models) to data from the 3S BRS project, where multiple behavioral responses of different severities had been observed per experimental exposure and per individual based upon expert scoring. We included species, signal type, exposure number and behavioral state prior to exposure as potential covariates. The best model included all main effect terms, with the exception of exposure number, as well as two interaction terms. The interactions between signal and behavioral state, and between species and behavioral state highlighted that the sensitivity of animals to different signal types (a 6–7 kHz upsweep sonar signal [MFAS] or a 1–2 kHz upsweep sonar signal [LFAS]) depended on their behavioral state (feeding or nonfeeding), and this differed across species. Of the three species included in this analysis (sperm whale [Physeter macrocephalus], killer whale [Orcinus orca] and long-finned pilot whale [Globicephala melas]), killer whales were consistently the most likely to exhibit behavioral responses to naval sonar exposure. We conclude that recurrent event survival analysis provides an effective framework for fitting dose-response severity functions to data from behavioral response studies. It can provide outputs that can help government and industry to evaluate the potential impacts of anthropogenic sound production in the ocean.
Fri, 20 Nov 2015 00:00:00 GMThttp://hdl.handle.net/10023/78452015-11-20T00:00:00ZHarris, Catriona MSadykova, DinaraDe Ruiter, Stacy LynnTyack, Peter LloydMiller, PatrickKvadsheim, PetterLam, Frans-PeterThomas, LenBehavioral response studies (BRSs) aim to enhance our understanding of the behavior changes made by animals in response to specific exposure levels of different stimuli, often presented in an increasing dosage. Here, we focus on BRSs that aim to understand behavioral responses of free-ranging whales and dolphins to manmade acoustic signals (although the methods are applicable more generally). One desired outcome of these studies is dose-response functions relevant to different species, signals and contexts. We adapted and applied recurrent event survival analysis (Cox proportional hazard models) to data from the 3S BRS project, where multiple behavioral responses of different severities had been observed per experimental exposure and per individual based upon expert scoring. We included species, signal type, exposure number and behavioral state prior to exposure as potential covariates. The best model included all main effect terms, with the exception of exposure number, as well as two interaction terms. The interactions between signal and behavioral state, and between species and behavioral state highlighted that the sensitivity of animals to different signal types (a 6–7 kHz upsweep sonar signal [MFAS] or a 1–2 kHz upsweep sonar signal [LFAS]) depended on their behavioral state (feeding or nonfeeding), and this differed across species. Of the three species included in this analysis (sperm whale [Physeter macrocephalus], killer whale [Orcinus orca] and long-finned pilot whale [Globicephala melas]), killer whales were consistently the most likely to exhibit behavioral responses to naval sonar exposure. We conclude that recurrent event survival analysis provides an effective framework for fitting dose-response severity functions to data from behavioral response studies. It can provide outputs that can help government and industry to evaluate the potential impacts of anthropogenic sound production in the ocean.Context-dependent associations between heterozygosity and immune variation in a wild carnivore Evolutionary ecology and behaviourhttp://hdl.handle.net/10023/7843
Background: A multitude of correlations between heterozygosity and fitness proxies associated with disease have been reported from wild populations, but the genetic basis of these associations is unresolved. We used a longitudinal dataset on wild Galapagos sea lions (Zalophus wollebaeki) to develop a relatively new perspective on this problem, by testing for associations between heterozygosity and immune variation across age classes and between ecological contexts. Results: Homozygosity by locus was negatively correlated with serum immunoglobulin G production in pups (0-3 months of age), suggesting that reduced genetic diversity has a detrimental influence on the early development of immune defence in the Galapagos sea lion. In addition, homozygosity by locus was positively correlated with total circulating leukocyte concentration in juveniles (6-24 months of age), but only in a colony subject to the anthropogenic environmental impacts of development, pollution and introduced species, which suggests that reduced genetic diversity influences mature immune system activity in circumstances of high antigen exposure. Conclusions: These findings demonstrate the environmental context-dependency of the phenotypic expression of immune variation, which is implicit in the theory of ecoimmunology, but which has been rarely demonstrated in the wild. They also indicate that heterozygosity may be linked to the maintenance of heterogeneity in mammalian immune system development and response to infection, adding to the body of evidence on the nature of the mechanistic link between heterozygosity and fitness.
Wed, 04 Nov 2015 00:00:00 GMThttp://hdl.handle.net/10023/78432015-11-04T00:00:00ZBrock, P.M.Goodman, S.J.Hall, Ailsa JaneCruz, M.Acevedo-Whitehouse, K.Background: A multitude of correlations between heterozygosity and fitness proxies associated with disease have been reported from wild populations, but the genetic basis of these associations is unresolved. We used a longitudinal dataset on wild Galapagos sea lions (Zalophus wollebaeki) to develop a relatively new perspective on this problem, by testing for associations between heterozygosity and immune variation across age classes and between ecological contexts. Results: Homozygosity by locus was negatively correlated with serum immunoglobulin G production in pups (0-3 months of age), suggesting that reduced genetic diversity has a detrimental influence on the early development of immune defence in the Galapagos sea lion. In addition, homozygosity by locus was positively correlated with total circulating leukocyte concentration in juveniles (6-24 months of age), but only in a colony subject to the anthropogenic environmental impacts of development, pollution and introduced species, which suggests that reduced genetic diversity influences mature immune system activity in circumstances of high antigen exposure. Conclusions: These findings demonstrate the environmental context-dependency of the phenotypic expression of immune variation, which is implicit in the theory of ecoimmunology, but which has been rarely demonstrated in the wild. They also indicate that heterozygosity may be linked to the maintenance of heterogeneity in mammalian immune system development and response to infection, adding to the body of evidence on the nature of the mechanistic link between heterozygosity and fitness.A general framework for animal density estimation from acoustic detections across a fixed microphone arrayhttp://hdl.handle.net/10023/7786
Acoustic monitoring can be an efficient, cheap, non-invasive alternative to physical trapping of individuals. Spatially explicit capture-recapture (SECR) methods have been proposed to estimate calling animal abundance and density from data collected by a fixed array of microphones. However, these methods make some assumptions that are unlikely to hold in many situations, and the consequences of violating these are yet to be investigated. We generalize existing acoustic SECR methodology, enabling these methods to be used in a much wider variety of situations. We incorporate time-of-arrival (TOA) data collected by the microphone array, increasing the precision of calling animal density estimates. We use our method to estimate calling male density of the Cape Peninsula Moss Frog Arthroleptella lightfooti. Our method gives rise to an estimator of calling animal density that has negligible bias, and 95% confidence intervals with appropriate coverage. We show that using TOA information can substantially improve estimate precision. Our analysis of the A. lightfooti data provides the first statistically rigorous estimate of calling male density for an anuran population using a microphone array. This method fills a methodological gap in the monitoring of frog populations and is applicable to acoustic monitoring of other species that call or vocalize.
Funding for the frog survey was received from the National Geographic Society/Waitt Grants Program (No. W184-11). The EPSRC and NERC helped to fund this research through a PhD grant (No. EP/I000917/1).
Thu, 01 Jan 2015 00:00:00 GMThttp://hdl.handle.net/10023/77862015-01-01T00:00:00ZStevenson, B.C.Borchers, D.L.Altwegg, R.Swift, R.J.Gillespie, D.M.Measey, G.J.Acoustic monitoring can be an efficient, cheap, non-invasive alternative to physical trapping of individuals. Spatially explicit capture-recapture (SECR) methods have been proposed to estimate calling animal abundance and density from data collected by a fixed array of microphones. However, these methods make some assumptions that are unlikely to hold in many situations, and the consequences of violating these are yet to be investigated. We generalize existing acoustic SECR methodology, enabling these methods to be used in a much wider variety of situations. We incorporate time-of-arrival (TOA) data collected by the microphone array, increasing the precision of calling animal density estimates. We use our method to estimate calling male density of the Cape Peninsula Moss Frog Arthroleptella lightfooti. Our method gives rise to an estimator of calling animal density that has negligible bias, and 95% confidence intervals with appropriate coverage. We show that using TOA information can substantially improve estimate precision. Our analysis of the A. lightfooti data provides the first statistically rigorous estimate of calling male density for an anuran population using a microphone array. This method fills a methodological gap in the monitoring of frog populations and is applicable to acoustic monitoring of other species that call or vocalize.Passive acoustic monitoring of beaked whale densities in the Gulf of Mexicohttp://hdl.handle.net/10023/7779
Beaked whales are deep diving elusive animals, difficult to census with conventional visual surveys. Methods are presented for the density estimation of beaked whales, using passive acoustic monitoring data collected at sites in the Gulf of Mexico (GOM) from the period during and following the Deepwater Horizon oil spill (2010–2013). Beaked whale species detected include: Gervais’ (Mesoplodon europaeus), Cuvier’s (Ziphius cavirostris), Blainville’s (Mesoplodon densirostris) and an unknown species of Mesoplodon sp. (designated as Beaked Whale Gulf — BWG). For Gervais’ and Cuvier’s beaked whales, we estimated weekly animal density using two methods, one based on the number of echolocation clicks, and another based on the detection of animal groups during 5 min time-bins. Density estimates derived from these two methods were in good general agreement. At two sites in the western GOM, Gervais’ beaked whales were present throughout the monitoring period, but Cuvier’s beaked whales were present only seasonally, with periods of low density during the summer and higher density in the winter. At an eastern GOM site, both Gervais’ and Cuvier’s beaked whales had a high density throughout the monitoring period.
Funding to support the tag data was also received from the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland) funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions.
Thu, 12 Nov 2015 00:00:00 GMThttp://hdl.handle.net/10023/77792015-11-12T00:00:00ZHildebrand, JohnBaumann-Pickering, SimoneFrasier, KaitlinTrickey, JenniferMerkens, KarlinaWiggins, SeanMcDonald, MarkGarrison, LanceHarris, DanielleMarques, Tiago A.Thomas, LenBeaked whales are deep diving elusive animals, difficult to census with conventional visual surveys. Methods are presented for the density estimation of beaked whales, using passive acoustic monitoring data collected at sites in the Gulf of Mexico (GOM) from the period during and following the Deepwater Horizon oil spill (2010–2013). Beaked whale species detected include: Gervais’ (Mesoplodon europaeus), Cuvier’s (Ziphius cavirostris), Blainville’s (Mesoplodon densirostris) and an unknown species of Mesoplodon sp. (designated as Beaked Whale Gulf — BWG). For Gervais’ and Cuvier’s beaked whales, we estimated weekly animal density using two methods, one based on the number of echolocation clicks, and another based on the detection of animal groups during 5 min time-bins. Density estimates derived from these two methods were in good general agreement. At two sites in the western GOM, Gervais’ beaked whales were present throughout the monitoring period, but Cuvier’s beaked whales were present only seasonally, with periods of low density during the summer and higher density in the winter. At an eastern GOM site, both Gervais’ and Cuvier’s beaked whales had a high density throughout the monitoring period.Status and future of research on the behavioural responses of marine mammals to U.S. Navy sonarhttp://hdl.handle.net/10023/7741
A review of the status and future of research into behavioral responses of marine mammals to naval sonar exposure was undertaken to evaluate the return on investment of current US Navy funded programs, identify the data needs and the contributions of current research programs to meeting data needs, and determine the ability to meet outstanding data needs given the current state of technology. As part of this review, a workshop was held from 21-22 April 2015 in Monterey, California. Workshop attendees were key representatives of Navy-funded behavioral response studies, as well as three external reviewers who were selected because of their expertise in animal behavior and behavioral responses to anthropogenic stimuli in the aquatic and terrestrial environments. Prior to the workshop, a questionnaire was circulated to canvass the opinions of members of the scientific community (primarily workshop attendees exclusive of external reviewers) on each of the research approaches taken to address this topic. The workshop was then structured around the questionnaire and responses received, via a series of discussion sessions. Afterwards, each research approach was evaluated independently by the external reviewers. This report presents a synthesis of the evaluations and recommendations of the external reviewers on current and future behavioral response research relevant to naval sonar. All reviewers agreed that excellent progress has been made on this topic and that each of the research approaches has contributed to our understanding of cetacean responses to naval sonar. The report includes specific comments and recommendations of the reviewers relevant to each approach, but also includes suggestions for priority species and a comprehensive list of recommendations for the future of BRS research in general (Tables 1 and 2). In summary it was recommended that BRS research be continued and extended to increase sample sizes and experimental replication, and temporal duration and spatial scale including more research in areas where the animals are presumably more naïve than on the naval ranges. It was noted that future investigations would benefit from combining experimentation and observation to enable linkage of short-term behavioral response to long-term fitness consequences of repeated exposure. Beaked whales were the species group ranked highest in terms of research priority. The importance of baseline studies and longer-term monitoring of animals before and after exposure is emphasized throughout.
Thu, 01 Jan 2015 00:00:00 GMThttp://hdl.handle.net/10023/77412015-01-01T00:00:00ZHarris, Catriona MThomas, LenA review of the status and future of research into behavioral responses of marine mammals to naval sonar exposure was undertaken to evaluate the return on investment of current US Navy funded programs, identify the data needs and the contributions of current research programs to meeting data needs, and determine the ability to meet outstanding data needs given the current state of technology. As part of this review, a workshop was held from 21-22 April 2015 in Monterey, California. Workshop attendees were key representatives of Navy-funded behavioral response studies, as well as three external reviewers who were selected because of their expertise in animal behavior and behavioral responses to anthropogenic stimuli in the aquatic and terrestrial environments. Prior to the workshop, a questionnaire was circulated to canvass the opinions of members of the scientific community (primarily workshop attendees exclusive of external reviewers) on each of the research approaches taken to address this topic. The workshop was then structured around the questionnaire and responses received, via a series of discussion sessions. Afterwards, each research approach was evaluated independently by the external reviewers. This report presents a synthesis of the evaluations and recommendations of the external reviewers on current and future behavioral response research relevant to naval sonar. All reviewers agreed that excellent progress has been made on this topic and that each of the research approaches has contributed to our understanding of cetacean responses to naval sonar. The report includes specific comments and recommendations of the reviewers relevant to each approach, but also includes suggestions for priority species and a comprehensive list of recommendations for the future of BRS research in general (Tables 1 and 2). In summary it was recommended that BRS research be continued and extended to increase sample sizes and experimental replication, and temporal duration and spatial scale including more research in areas where the animals are presumably more naïve than on the naval ranges. It was noted that future investigations would benefit from combining experimentation and observation to enable linkage of short-term behavioral response to long-term fitness consequences of repeated exposure. Beaked whales were the species group ranked highest in terms of research priority. The importance of baseline studies and longer-term monitoring of animals before and after exposure is emphasized throughout.Finescale ecological niche modeling provides evidence that lactating gray seals (Halichoerus grypus) prefer access to fresh water in order to drinkhttp://hdl.handle.net/10023/7740
Many phocids are capital breeders, relying on stored reserves to sustain energetic requirements while on land. Their large body size, high energy expenditure during lactation, and the insulative effects of the blubber layer can lead to thermal stress from overheating, especially in warm and temperate climates. Thermal stress can influence fine-scale site choice on breeding colonies, and behavioral thermoregulation has been proposed as an explanation for the clear preferences shown by breeding female gray seals for proximity to pools of water. However, anecdotal observations suggest that pools of water may also be preferred for drinking, though water intake is difficult to verify without real-time physiological monitoring. Here, an alternative approach demonstrates that gray seals also require access to water for drinking. Using Ecological Niche Factor Analysis to examine fine-scale physical determinants of pupping site choice at North Rona, Scotland, we found that lactating mothers showed preference for lower salinity pools. This is most pronounced early in the season, when ambient temperatures and presumably thermal stress are greatest. Given that the cooling effect of fresh and salt water should be equivalent, the most parsimonious explanation for this preference for fresh water pools is that lactating females use these pools for drinking.
Wed, 01 Oct 2014 00:00:00 GMThttp://hdl.handle.net/10023/77402014-10-01T00:00:00ZStewart, J.E.Pomeroy, P.P.Duck, C.D.Twiss, S.D.Many phocids are capital breeders, relying on stored reserves to sustain energetic requirements while on land. Their large body size, high energy expenditure during lactation, and the insulative effects of the blubber layer can lead to thermal stress from overheating, especially in warm and temperate climates. Thermal stress can influence fine-scale site choice on breeding colonies, and behavioral thermoregulation has been proposed as an explanation for the clear preferences shown by breeding female gray seals for proximity to pools of water. However, anecdotal observations suggest that pools of water may also be preferred for drinking, though water intake is difficult to verify without real-time physiological monitoring. Here, an alternative approach demonstrates that gray seals also require access to water for drinking. Using Ecological Niche Factor Analysis to examine fine-scale physical determinants of pupping site choice at North Rona, Scotland, we found that lactating mothers showed preference for lower salinity pools. This is most pronounced early in the season, when ambient temperatures and presumably thermal stress are greatest. Given that the cooling effect of fresh and salt water should be equivalent, the most parsimonious explanation for this preference for fresh water pools is that lactating females use these pools for drinking.Predicting future European breeding distributions of British seabird species under climate change and unlimited/no dispersal scenarioshttp://hdl.handle.net/10023/7735
Understanding which traits make species vulnerable to climatic change and predicting future distributions permits conservation efforts to be focused on the most vulnerable species and the most appropriate sites. Here, we combine climate envelope models with predicted bioclimatic data from two emission scenarios leading up to 2100, to predict European breeding distributions of 23 seabird species that currently breed in the British Isles. Assuming unlimited dispersal, some species would be “winners” (increase the size of their range), but over 65% would lose range, some by up to 80%. These “losers” have a high vulnerability to low prey availability, and a northerly distribution meaning they would lack space to move into. Under the worst-case scenario of no dispersal, species are predicted to lose between 25% and 100% of their range, so dispersal ability is a key constraint on future range sizes. More globally, the results indicate, based on foraging ecology, which seabird species are likely to be most affected by climatic change. Neither of the emissions scenarios used in this study is extreme, yet they generate very different predictions for some species, illustrating that even small decreases in emissions could yield large benefits for conservation.
We thank the European Bird Census Council for their data on European seabird distributions. DJFR was supported by NERC UKPopNet.
Mon, 02 Nov 2015 00:00:00 GMThttp://hdl.handle.net/10023/77352015-11-02T00:00:00ZRussell, Deborah Jill FraserWanless, SarahCollingham, Yvonne C.Huntley, BrianHamer, Keith C.Understanding which traits make species vulnerable to climatic change and predicting future distributions permits conservation efforts to be focused on the most vulnerable species and the most appropriate sites. Here, we combine climate envelope models with predicted bioclimatic data from two emission scenarios leading up to 2100, to predict European breeding distributions of 23 seabird species that currently breed in the British Isles. Assuming unlimited dispersal, some species would be “winners” (increase the size of their range), but over 65% would lose range, some by up to 80%. These “losers” have a high vulnerability to low prey availability, and a northerly distribution meaning they would lack space to move into. Under the worst-case scenario of no dispersal, species are predicted to lose between 25% and 100% of their range, so dispersal ability is a key constraint on future range sizes. More globally, the results indicate, based on foraging ecology, which seabird species are likely to be most affected by climatic change. Neither of the emissions scenarios used in this study is extreme, yet they generate very different predictions for some species, illustrating that even small decreases in emissions could yield large benefits for conservation.Beaked whaleshttp://hdl.handle.net/10023/7734
Mon, 18 Aug 2014 00:00:00 GMThttp://hdl.handle.net/10023/77342014-08-18T00:00:00ZMadsen, PeterAguilar de Soto, NatachaTyack, Peter LloydJohnson, MarkSound production and associated behavior of tagged fin whales (Balaenoptera physalus) in the Southern California Bighthttp://hdl.handle.net/10023/7716
Background: For marine animals, acoustic communication is critical for many life functions, yet individual calling behavior is poorly understood for most large whale species. These topics are important for understanding whale social behavior and can also serve as a baseline for behavioral studies assessing whale response to disturbance. Using a new technique for identifying the calling individual, we measured body orientation, dive behavior, and surface social behavior in relation to call production for tagged fin whales in Southern California. Results: Behavioral metrics associated with elevated call rates included shallow maximum dive depths (10–15 m), little body movement, negative pitch in body orientation, and moderate body roll. Calling whales were also more likely to be traveling than milling, in groups rather than solitary, and without change in group size compared to non-calling whales. Conclusions: These are the first descriptions of body posture and depths at which fin whales are most likely to call, and some possible sound propagation and/or anatomical reasons for these results are considered. The call behavior characterizations presented here will help in predicting calling behavior from surface behavior, informing interpretation of passive acoustic data, and determining the effects of anthropogenic sound on whales in Southern California.
Mon, 03 Aug 2015 00:00:00 GMThttp://hdl.handle.net/10023/77162015-08-03T00:00:00ZStimpert, AlisonDeRuiter, StacyFalcone, ErinJoseph, JohnDouglas, Annie BMoretti, David JFriedlander, Ari SCalambokidis, JohnGailey, GlennTyack, Peter LloydGoldbogen, Jeremy ABackground: For marine animals, acoustic communication is critical for many life functions, yet individual calling behavior is poorly understood for most large whale species. These topics are important for understanding whale social behavior and can also serve as a baseline for behavioral studies assessing whale response to disturbance. Using a new technique for identifying the calling individual, we measured body orientation, dive behavior, and surface social behavior in relation to call production for tagged fin whales in Southern California. Results: Behavioral metrics associated with elevated call rates included shallow maximum dive depths (10–15 m), little body movement, negative pitch in body orientation, and moderate body roll. Calling whales were also more likely to be traveling than milling, in groups rather than solitary, and without change in group size compared to non-calling whales. Conclusions: These are the first descriptions of body posture and depths at which fin whales are most likely to call, and some possible sound propagation and/or anatomical reasons for these results are considered. The call behavior characterizations presented here will help in predicting calling behavior from surface behavior, informing interpretation of passive acoustic data, and determining the effects of anthropogenic sound on whales in Southern California.The east coast of Scotland bottlenose dolphin population : improving understanding of ecology outside the Moray Firth SAChttp://hdl.handle.net/10023/7708
Wed, 07 May 2014 00:00:00 GMThttp://hdl.handle.net/10023/77082014-05-07T00:00:00ZQuick, Nicola JaneArso Civil, MonicaCheney, BarbaraIslas Villanueva, ValentinaJanik, VincentThompson, PaulHammond, Philip StevenThe generalized data management and collection protocol for Conductivity-Temperature-Depth Satellite Relay Data Loggershttp://hdl.handle.net/10023/7676
The software routines for data sampling and processing that are implemented on-board telemetry devices (tags) called Conductivity-Temperature-Depth Satellite Relay Data Loggers (CTD-SRDLs) enable the simultaneous collection of biological and in-situ environmental data by animal-platforms over periods of weeks to months, despite severe energy and bandwidth limitations imposed by their relatively small size. This extended operational lifetime is made possible by the use of software protocols on-board the tags that manage sensors, data collection, storage, compression and transmission to ensure that the most useful data are sent at appropriate resolution while minimizing redundancy. While tag software is tailored to the particular species under study and the questions being addressed with a given field deployment, the philosophy behind Sea Mammal Research Unit Instrumentation Group (SMRU-IG) software protocols is to adopt a general set of principles to achieve the best results within the energy and bandwidth constraints. Here, we discuss these and review the general protocol that is used to simultaneously collect information on geographical movements, diving behaviour and in-situ oceanographic information from marine mammals.
Wed, 29 Jul 2015 00:00:00 GMThttp://hdl.handle.net/10023/76762015-07-29T00:00:00ZPhotopoulou, TheoniFedak, MikeMatthiopoulos, JasonMcConnell, Bernie JLovell, PhilipThe software routines for data sampling and processing that are implemented on-board telemetry devices (tags) called Conductivity-Temperature-Depth Satellite Relay Data Loggers (CTD-SRDLs) enable the simultaneous collection of biological and in-situ environmental data by animal-platforms over periods of weeks to months, despite severe energy and bandwidth limitations imposed by their relatively small size. This extended operational lifetime is made possible by the use of software protocols on-board the tags that manage sensors, data collection, storage, compression and transmission to ensure that the most useful data are sent at appropriate resolution while minimizing redundancy. While tag software is tailored to the particular species under study and the questions being addressed with a given field deployment, the philosophy behind Sea Mammal Research Unit Instrumentation Group (SMRU-IG) software protocols is to adopt a general set of principles to achieve the best results within the energy and bandwidth constraints. Here, we discuss these and review the general protocol that is used to simultaneously collect information on geographical movements, diving behaviour and in-situ oceanographic information from marine mammals.Can a gray seal (Halichoerus grypus) generalize call classes?http://hdl.handle.net/10023/7670
Past researchers have found that gray seals (Halichoerus grypus) are capable of classifying vocal signals by call type using a trained set, but were unable to generalize to novel exemplars (Shapiro, Slater, & Janik, 2004). Given the importance of auditory categorization in communication, it would be surprising if the animals were unable to generalize acoustically similar calls into classes. Here, we trained a juvenile gray seal to discriminate novel calls into 2 classes, “growls” and “moans,” by vocally matching call types (i.e., the seal moaned when played a moan and growled when played a growl). Our method differed from the previous study as we trained the animal using a comparatively large set of exemplars with standardized durations, consisting of both the seal’s own calls and those of 2 other seals. The seal successfully discriminated growls and moans for both her own (94% correct choices) and the other seals’ (87% correct choices) calls. We used a generalized linear model (GLM) and found that the seal’s performance significantly improved across test sessions, and that accuracy was higher during the first presentation of a sound from her own repertoire but decreased after multiple exposures. This pattern was not found for calls from unknown seals. Factor analysis for mixed data (FAMD) identified acoustic parameters that could be used to discriminate between call types and individuals. Growls and moans differed in noise, duration and frequency parameters, whereas individuals differed only in frequency. These data suggest that the seal could have gained information about both call type and caller identity using frequency cues.
Sun, 01 Nov 2015 00:00:00 GMThttp://hdl.handle.net/10023/76702015-11-01T00:00:00ZStansbury, Amandade Freitas, MafaldaWu, Gi-MickJanik, Vincent M.Past researchers have found that gray seals (Halichoerus grypus) are capable of classifying vocal signals by call type using a trained set, but were unable to generalize to novel exemplars (Shapiro, Slater, & Janik, 2004). Given the importance of auditory categorization in communication, it would be surprising if the animals were unable to generalize acoustically similar calls into classes. Here, we trained a juvenile gray seal to discriminate novel calls into 2 classes, “growls” and “moans,” by vocally matching call types (i.e., the seal moaned when played a moan and growled when played a growl). Our method differed from the previous study as we trained the animal using a comparatively large set of exemplars with standardized durations, consisting of both the seal’s own calls and those of 2 other seals. The seal successfully discriminated growls and moans for both her own (94% correct choices) and the other seals’ (87% correct choices) calls. We used a generalized linear model (GLM) and found that the seal’s performance significantly improved across test sessions, and that accuracy was higher during the first presentation of a sound from her own repertoire but decreased after multiple exposures. This pattern was not found for calls from unknown seals. Factor analysis for mixed data (FAMD) identified acoustic parameters that could be used to discriminate between call types and individuals. Growls and moans differed in noise, duration and frequency parameters, whereas individuals differed only in frequency. These data suggest that the seal could have gained information about both call type and caller identity using frequency cues.The modelling and assessment of whale-watching impactshttp://hdl.handle.net/10023/7642
In recent years there has been significant interest in modelling cumulative effects and the population consequences of individual changes in cetacean behaviour and physiology due to disturbance. One potential source of disturbance that has garnered particular interest is whale-watching. Though perceived as 'green' or eco-friendly tourism, there is evidence that whale-watching can result in statistically significant and biologically meaningful changes in cetacean behaviour, raising the question whether whale-watching is in fact a long term sustainable activity. However, an assessment of the impacts of whale-watching on cetaceans requires an understanding of the potential behavioural and physiological effects, data to effectively address the question and suitable modelling techniques. Here, we review the current state of knowledge on the viability of long-term whale-watching, as well as logistical limitations and potential opportunities. We conclude that an integrated, coordinated approach will be needed to further understanding of the possible effects of whale-watching on cetaceans.
Thu, 01 Oct 2015 00:00:00 GMThttp://hdl.handle.net/10023/76422015-10-01T00:00:00ZNew, Leslie FrancesHall, Ailsa JaneHarcourt, R.Kaufman, G.Parsons, E.C.M.Pearson, H.C.Cosentino, A.M.Schick, Robert SchillingIn recent years there has been significant interest in modelling cumulative effects and the population consequences of individual changes in cetacean behaviour and physiology due to disturbance. One potential source of disturbance that has garnered particular interest is whale-watching. Though perceived as 'green' or eco-friendly tourism, there is evidence that whale-watching can result in statistically significant and biologically meaningful changes in cetacean behaviour, raising the question whether whale-watching is in fact a long term sustainable activity. However, an assessment of the impacts of whale-watching on cetaceans requires an understanding of the potential behavioural and physiological effects, data to effectively address the question and suitable modelling techniques. Here, we review the current state of knowledge on the viability of long-term whale-watching, as well as logistical limitations and potential opportunities. We conclude that an integrated, coordinated approach will be needed to further understanding of the possible effects of whale-watching on cetaceans.Impacts of anthropogenic noise on marine life : publication patterns, new discoveries, and future directions in research and managementhttp://hdl.handle.net/10023/7640
Anthropogenic underwater noise is now recognized as a world-wide problem, and recent studies have shown a broad range of negative effects in a variety of taxa. Underwater noise from shipping is increasingly recognized as a significant and pervasive pollutant with the potential to impact marine ecosystems on a global scale. We reviewed six regional case studies as examples of recent research and management activities relating to ocean noise in a variety of taxonomic groups, locations, and approaches. However, as no six projects could ever cover all taxa, sites and noise sources, a brief bibliometric analysis places these case studies into the broader historical and topical context of the peer-reviewed ocean noise literature as a whole. The case studies highlighted emerging knowledge of impacts, including the ways that non-injurious effects can still accumulate at the population level, and detailed approaches to guide ocean noise management. They build a compelling case that a number of anthropogenic noise types can affect a variety of marine taxa. Meanwhile, the bibliometric analyses revealed an increasing diversity of ocean noise topics covered and journal outlets since the 1940s. This could be seen in terms of both the expansion of the literature from more physical interests to ecological impacts of noise, management and policy, and consideration of a widening range of taxa. However, if our scientific knowledge base is ever to get ahead of the curve of rapid industrialization of the ocean, we are going to have to identify naïve populations and relatively pristine seas, and construct mechanistic models, so that we can predict impacts before they occur, and guide effective mitigation for the most vulnerable populations.
Funding for R. Bruintjes, J. Purser, A. N. Radford, S. D, Simpson and M. A. Wale was provided by the UK Department for Environment Food and Rural Affairs (Defra). N.D. Merchant received travel funding from Ocean Networks Canada. RW was supported by a Marie Curie International Incoming Fellowship within the 7th European Community Framework Programme (Project CONCEAL, FP7, PIIF-GA-2009-253407), and received travel funding to attend IMCC3 from the Society for Conservation Biology (SCB) Marine Section and the International Whaling Commission’s Climate Change steering group (with thanks to Mark Simmonds). A.J. Wright also received travel funding to attend IMCC3 from the SCB Marine Section. Date of Acceptance: 28/05/2015
Thu, 01 Oct 2015 00:00:00 GMThttp://hdl.handle.net/10023/76402015-10-01T00:00:00ZWilliams, RobertWright, Andrew JAshe, ErinBlight, LKBruintjes, RCanessa, RClark, CWCullis-Suzuki, SDakin, DTErbe, CHammond, Philip StevenMerchant, MDO'Hara, PDPurser, JRadford, ANSimpson, SDThomas, LenWale, MAAnthropogenic underwater noise is now recognized as a world-wide problem, and recent studies have shown a broad range of negative effects in a variety of taxa. Underwater noise from shipping is increasingly recognized as a significant and pervasive pollutant with the potential to impact marine ecosystems on a global scale. We reviewed six regional case studies as examples of recent research and management activities relating to ocean noise in a variety of taxonomic groups, locations, and approaches. However, as no six projects could ever cover all taxa, sites and noise sources, a brief bibliometric analysis places these case studies into the broader historical and topical context of the peer-reviewed ocean noise literature as a whole. The case studies highlighted emerging knowledge of impacts, including the ways that non-injurious effects can still accumulate at the population level, and detailed approaches to guide ocean noise management. They build a compelling case that a number of anthropogenic noise types can affect a variety of marine taxa. Meanwhile, the bibliometric analyses revealed an increasing diversity of ocean noise topics covered and journal outlets since the 1940s. This could be seen in terms of both the expansion of the literature from more physical interests to ecological impacts of noise, management and policy, and consideration of a widening range of taxa. However, if our scientific knowledge base is ever to get ahead of the curve of rapid industrialization of the ocean, we are going to have to identify naïve populations and relatively pristine seas, and construct mechanistic models, so that we can predict impacts before they occur, and guide effective mitigation for the most vulnerable populations.Images as proximity sensors : the incidence of conspecific foraging in Antarctic fur sealshttp://hdl.handle.net/10023/7581
Background: Although there have been recent advances in the development of animal-attached ‘proximity’ tags to remotely record the interactions of multiple individuals, the efficacy of these devices depends on the instrumentation of sufficient animals that subsequently have spatial interactions. Among densely colonial mammals such as fur seals, this remains logistically difficult, and interactions between animals during foraging have not previously been recorded. Results: We collected data on conspecific interactions during diving at sea using still image and video cameras deployed on 23 Antarctic fur seals. Animals carried cameras for a total of 152 days, collecting 38,098 images and 369 movies (total time 7.35 h). Other fur seals were detected in 74% of deployments, with a maximum of five seals seen at one time (n = 122 images, 28 videos). No predators other than conspecifics were observed. Detection was primarily limited by light conditions, since conspecifics were usually further from each other than the 1-m range illuminated by camera flash under low light levels. Other seals were recorded at a range of depths (average 27 ± 14.3 m, max 66 m). In terms of bouts of dives, still images of other seals were recorded in 5 single dives (of 330) and 28 bouts of dives <2 min apart (of 187). Linear mixed models suggested a relationship between conspecific observations per dive and the number of krill images recorded per dive. Using light conditions as a proxy for detectability, other seals were more likely to be observed at the bottom of dives than during descent or ascent. Seals were also more likely to be closer to each other and oriented perpendicular to each other at the bottom of dives, and in the same direction as each other during ascent. Conclusions: These results are contrary to animal-attached camera observations of penguin foraging, suggesting differing group-foraging tactics for these marine predators. Group foraging could have consequences for models linking predator behaviour to prey field densities since this relationship may be affected by the presence of multiple predators at the same patch.
Tue, 29 Sep 2015 00:00:00 GMThttp://hdl.handle.net/10023/75812015-09-29T00:00:00ZHooker, Sascha KateBarychka, TatsianaJessopp, Mark JStaniland, Iain JBackground: Although there have been recent advances in the development of animal-attached ‘proximity’ tags to remotely record the interactions of multiple individuals, the efficacy of these devices depends on the instrumentation of sufficient animals that subsequently have spatial interactions. Among densely colonial mammals such as fur seals, this remains logistically difficult, and interactions between animals during foraging have not previously been recorded. Results: We collected data on conspecific interactions during diving at sea using still image and video cameras deployed on 23 Antarctic fur seals. Animals carried cameras for a total of 152 days, collecting 38,098 images and 369 movies (total time 7.35 h). Other fur seals were detected in 74% of deployments, with a maximum of five seals seen at one time (n = 122 images, 28 videos). No predators other than conspecifics were observed. Detection was primarily limited by light conditions, since conspecifics were usually further from each other than the 1-m range illuminated by camera flash under low light levels. Other seals were recorded at a range of depths (average 27 ± 14.3 m, max 66 m). In terms of bouts of dives, still images of other seals were recorded in 5 single dives (of 330) and 28 bouts of dives <2 min apart (of 187). Linear mixed models suggested a relationship between conspecific observations per dive and the number of krill images recorded per dive. Using light conditions as a proxy for detectability, other seals were more likely to be observed at the bottom of dives than during descent or ascent. Seals were also more likely to be closer to each other and oriented perpendicular to each other at the bottom of dives, and in the same direction as each other during ascent. Conclusions: These results are contrary to animal-attached camera observations of penguin foraging, suggesting differing group-foraging tactics for these marine predators. Group foraging could have consequences for models linking predator behaviour to prey field densities since this relationship may be affected by the presence of multiple predators at the same patch.Ultrasonic vocalizations of female Norway rats (Rattus norvegicus) in response to social partnershttp://hdl.handle.net/10023/7555
In many species of animals, male vocalizations function to attract mating partners and coordinate sexual interactions. While male vocalizations have been well studied in several species, the function of female vocalizations in mating contexts is not fully understood. In Norway rats (Rattus norvegicus), both males and females produce ultrasonic vocalizations (USVs) during sexual encounters with opposite-sex partners. The aim of this study was to test the hypothesis that female vocalizations play a role in sociosexual interactions by examining how rates of 50kHz USV production vary in relation to the sex and gonadal status of the partner, and by examining whether the proportion of frequency modulated (FM) and constant frequency calls differs between these categories of social partner. The results showed that females produced a higher total number of 50kHz USVs to intact males than castrated males, and produced similar numbers of calls to both categories of females. Females also produced a higher proportion of FM calls to male partners than to female partners, and spent more time in the vicinity of male than female partners, regardless of the partners’ gonadal status. Female USVs therefore potentially provide a measure of sexual motivation and may function to promote female mate choice in this species with multi-male mating and a high risk of infanticide.
Funding was provided by School of Psychology & Neuroscience and Institute of Behavioural and Neural Sciences, University of St Andrews.
Mon, 01 Feb 2016 00:00:00 GMThttp://hdl.handle.net/10023/75552016-02-01T00:00:00ZBörner, AnnegretHjemdahl, RebeccaGotz, ThomasBrown, Gillian RuthIn many species of animals, male vocalizations function to attract mating partners and coordinate sexual interactions. While male vocalizations have been well studied in several species, the function of female vocalizations in mating contexts is not fully understood. In Norway rats (Rattus norvegicus), both males and females produce ultrasonic vocalizations (USVs) during sexual encounters with opposite-sex partners. The aim of this study was to test the hypothesis that female vocalizations play a role in sociosexual interactions by examining how rates of 50kHz USV production vary in relation to the sex and gonadal status of the partner, and by examining whether the proportion of frequency modulated (FM) and constant frequency calls differs between these categories of social partner. The results showed that females produced a higher total number of 50kHz USVs to intact males than castrated males, and produced similar numbers of calls to both categories of females. Females also produced a higher proportion of FM calls to male partners than to female partners, and spent more time in the vicinity of male than female partners, regardless of the partners’ gonadal status. Female USVs therefore potentially provide a measure of sexual motivation and may function to promote female mate choice in this species with multi-male mating and a high risk of infanticide.Assessing use of and reaction to unmanned aerial systems in gray and harbor seals during breeding and molt in the UKhttp://hdl.handle.net/10023/7486
Wildlife biology applications of unmanned aerial systems (UAS) are extensive. Survey, identification, and measurement using UAS equipped with appropriate sensors can now be added to the suite of techniques available for monitoring animals – here we detail our experiences in using UAS to obtain detailed information from groups of seals, which can be difficult to observe from land. Trial flights to survey grey and harbour seals using a range of different platforms and imaging systems have been carried out with varying success at a number of sites in Scotland over the last two years. The best performing UAS system was determined by site, field situation, and the data required. Our systems routinely allow relative abundance, species, age--class, and individual identity to be obtained from images currently, with measures of body size also obtainable but open to refinement. However, the impacts of UAS on target species can also be variable and should be monitored closely. We found variable responses to UAS flights, likely related to the animals’ experience of previous disturbance.
This work was supported by UK NERC National Environmental Research Council National Capability funding to SMRU, NERC grant No. GE08-001358 to PP, through UK DEFRA support to SMRU, and by development grants from MASTS and Chester Zoo.
Tue, 15 Sep 2015 00:00:00 GMThttp://hdl.handle.net/10023/74862015-09-15T00:00:00ZPomeroy, PatrickO’Connor, L.Davies, P.Wildlife biology applications of unmanned aerial systems (UAS) are extensive. Survey, identification, and measurement using UAS equipped with appropriate sensors can now be added to the suite of techniques available for monitoring animals – here we detail our experiences in using UAS to obtain detailed information from groups of seals, which can be difficult to observe from land. Trial flights to survey grey and harbour seals using a range of different platforms and imaging systems have been carried out with varying success at a number of sites in Scotland over the last two years. The best performing UAS system was determined by site, field situation, and the data required. Our systems routinely allow relative abundance, species, age--class, and individual identity to be obtained from images currently, with measures of body size also obtainable but open to refinement. However, the impacts of UAS on target species can also be variable and should be monitored closely. We found variable responses to UAS flights, likely related to the animals’ experience of previous disturbance.A Southern Indian Ocean database of hydrographic profiles obtained with instrumented elephant sealshttp://hdl.handle.net/10023/7457
The instrumentation of southern elephant seals with satellite-linked CTD tags has offered unique temporal and spatial coverage of the Southern Indian Ocean since 2004. This includes extensive data from the Antarctic continental slope and shelf regions during the winter months, which is outside the conventional areas of Argo autonomous floats and ship-based studies. This landmark dataset of around 75,000 temperature and salinity profiles from 20–140 °E, concentrated on the sector between the Kerguelen Islands and Prydz Bay, continues to grow through the coordinated efforts of French and Australian marine research teams. The seal data are quality controlled and calibrated using delayed-mode techniques involving comparisons with other existing profiles as well as cross-comparisons similar to established protocols within the Argo community, with a resulting accuracy of ±0.03 °C in temperature and ±0.05 in salinity or better. The data offer invaluable new insights into the water masses, oceanographic processes and provides a vital tool for oceanographers seeking to advance our understanding of this key component of the global ocean climate.
Tue, 02 Sep 2014 00:00:00 GMThttp://hdl.handle.net/10023/74572014-09-02T00:00:00ZRoquet, FabienWilliams, GuyHindell, Mark A.Harcourt, RobMcMahon, CliveGuinet, ChristopheCharrassin, Jean-BenoitReverdin, GillesBoehme, LarsLovell, PhilipFedak, MikeThe instrumentation of southern elephant seals with satellite-linked CTD tags has offered unique temporal and spatial coverage of the Southern Indian Ocean since 2004. This includes extensive data from the Antarctic continental slope and shelf regions during the winter months, which is outside the conventional areas of Argo autonomous floats and ship-based studies. This landmark dataset of around 75,000 temperature and salinity profiles from 20–140 °E, concentrated on the sector between the Kerguelen Islands and Prydz Bay, continues to grow through the coordinated efforts of French and Australian marine research teams. The seal data are quality controlled and calibrated using delayed-mode techniques involving comparisons with other existing profiles as well as cross-comparisons similar to established protocols within the Argo community, with a resulting accuracy of ±0.03 °C in temperature and ±0.05 in salinity or better. The data offer invaluable new insights into the water masses, oceanographic processes and provides a vital tool for oceanographers seeking to advance our understanding of this key component of the global ocean climate.International Quiet Ocean Experiment science planhttp://hdl.handle.net/10023/7411
Thu, 01 Jan 2015 00:00:00 GMThttp://hdl.handle.net/10023/74112015-01-01T00:00:00ZLarge scale surveys for cetaceans : line transect assumptions, reliability of abundance estimates and improving survey efficiency – A response to MacLeodhttp://hdl.handle.net/10023/7159
Sat, 01 Feb 2014 00:00:00 GMThttp://hdl.handle.net/10023/71592014-02-01T00:00:00ZHammond, Philip StevenGillespie, Douglas MichaelLovell, PhilipSamarra, Filipa Isabel PereiraSwift, Rene JamesMacleod, KellyTasker, Mark LBerggren, PerBorchers, David LouisBurt, M LouisePaxton, Charles G. M.Canadas, AnaDesportes, GenevieveDonovan, Greg PGilles, AnitaLehnert, KristinaSiebert, UrsulaGordon, Jonathan Charles DavidLeaper, RussellLeopold, MardikScheidat, MeikeOien, NilsRidoux, VincentRogan, EmerSkov, HenrikTeilmann, JonasVan Canneyt, OlivierVazquez, Jose AntonioAssessing the potential of autonomous submarine gliders for ecosystem monitoring across multiple trophic levels (plankton to cetaceans) and pollutants in shallow shelf seashttp://hdl.handle.net/10023/6995
A combination of scientific, economic, technological and policy drivers is behind a recent upsurge in the use of marine autonomous systems (and accompanying miniaturized sensors) for environmental mapping and monitoring. Increased spatial-temporal resolution and coverage of data, at reduced cost, is particularly vital for effective spatial management of highly dynamic and heterogeneous shelf environments. This proof-of-concept study involves integration of a novel combination of sensors onto buoyancy-driven submarine gliders, in order to assess their suitability for ecosystem monitoring in shelf waters at a variety of trophic levels. Two shallow-water Slocum gliders were equipped with CTD and fluorometer to measure physical properties and chlorophyll, respectively. One glider was also equipped with a single-frequency echosounder to collect information on zooplankton and fish distribution. The other glider carried a Passive Acoustic Monitoring system to detect and record cetacean vocalizations, and a passive sampler to detect chemical contaminants in the water column. The two gliders were deployed together off southwest UK in autumn 2013, and targeted a known tidal-mixing front west of the Isles of Scilly. The gliders' mission took about 40 days, with each glider travelling distances of >1000km and undertaking >2500 dives to depths of up to 100m. Controlling glider flight and alignment of the two glider trajectories proved to be particularly challenging due to strong tidal flows. However, the gliders continued to collect data in poor weather when an accompanying research vessel was unable to operate. In addition, all glider sensors generated useful data, with particularly interesting initial results relating to subsurface chlorophyll maxima and numerous fish/cetacean detections within the water column. The broader implications of this study for marine ecosystem monitoring with submarine gliders are discussed.
The Gliders and AUVs for Marine Observation and Research (GLAMOR) project was primarily funded by UK Department for the Environment, Food and Rural Affairs (Defra), through their Strategic Evidence and Partnerships Fund. Damien Guihen was funded by Natural Environment Research Council (NERC) grant NE/H014756/1. Additional financial support came through Defra project MF1112 (POSEIDON). Ian Allan (NIVA) and Branislav Vrana (RECETOX) acknowledge funding from the European Union Seventh Framework Programme (FP7/2007–2013) under grant agreement no. 262584, JERICO (TNA project GLISS).
Mon, 01 Sep 2014 00:00:00 GMThttp://hdl.handle.net/10023/69952014-09-01T00:00:00ZSuberg, L.Wynn, R.B.Kooij, J.V.D.Fernand, L.Fielding, S.Guihen, D.Gillespie, D.Johnson, M.Gkikopoulou, K.C.Allan, I.J.Vrana, B.Miller, P.I.Smeed, D.Jones, A.R.A combination of scientific, economic, technological and policy drivers is behind a recent upsurge in the use of marine autonomous systems (and accompanying miniaturized sensors) for environmental mapping and monitoring. Increased spatial-temporal resolution and coverage of data, at reduced cost, is particularly vital for effective spatial management of highly dynamic and heterogeneous shelf environments. This proof-of-concept study involves integration of a novel combination of sensors onto buoyancy-driven submarine gliders, in order to assess their suitability for ecosystem monitoring in shelf waters at a variety of trophic levels. Two shallow-water Slocum gliders were equipped with CTD and fluorometer to measure physical properties and chlorophyll, respectively. One glider was also equipped with a single-frequency echosounder to collect information on zooplankton and fish distribution. The other glider carried a Passive Acoustic Monitoring system to detect and record cetacean vocalizations, and a passive sampler to detect chemical contaminants in the water column. The two gliders were deployed together off southwest UK in autumn 2013, and targeted a known tidal-mixing front west of the Isles of Scilly. The gliders' mission took about 40 days, with each glider travelling distances of >1000km and undertaking >2500 dives to depths of up to 100m. Controlling glider flight and alignment of the two glider trajectories proved to be particularly challenging due to strong tidal flows. However, the gliders continued to collect data in poor weather when an accompanying research vessel was unable to operate. In addition, all glider sensors generated useful data, with particularly interesting initial results relating to subsurface chlorophyll maxima and numerous fish/cetacean detections within the water column. The broader implications of this study for marine ecosystem monitoring with submarine gliders are discussed.Experimental evidence for the co-evolution of hominin tool-making teaching and languagehttp://hdl.handle.net/10023/6970
Hominin reliance on Oldowan stone tools—which appear from 2.5 mya and are believed to have been socially transmitted—has been hypothesized to have led to the evolution of teaching and language. Here we present an experiment investigating the efficacy of transmission of Oldowan tool-making skills along chains of adult human participants (N=184) using five different transmission mechanisms. Across six measures, transmission improves with teaching, and particularly with language, but not with imitation or emulation. Our results support the hypothesis that hominin reliance on stone tool-making generated selection for teaching and language, and imply that (i) low-fidelity social transmission, such as imitation/emulation, may have contributed to the ~700,000 year stasis of the Oldowan technocomplex, and (ii) teaching or proto-language may have been pre-requisites for the appearance of Acheulean technology. This work supports a gradual evolution of language, with simple symbolic communication preceding behavioural modernity by hundreds of thousands of years.
Research supported in part by an ERC Advanced Grant to K.N.L. (EVOCULTURE, ref: 232823) and grants to N.T.U. from the British Academy (Centenary Project ‘Lucy to Language: the Archaeology of the Social Brain’) and the Leverhulme Trust (ECF 0298). Supplementary information available for this article at http://www.nature.com/ncomms/2015/150113/ncomms7029/suppinfo/ncomms7029_S1.html
Tue, 13 Jan 2015 00:00:00 GMThttp://hdl.handle.net/10023/69702015-01-13T00:00:00ZMorgan, T. J. H.Uomini, N. T.Rendell, L. E.Chouinard-Thuly, L.Street, S. E.Lewis, H. M.Cross, C. P.Evans, C.Kearney, R.de la Torre, I.Whiten, A.Laland, K. N.Hominin reliance on Oldowan stone tools—which appear from 2.5 mya and are believed to have been socially transmitted—has been hypothesized to have led to the evolution of teaching and language. Here we present an experiment investigating the efficacy of transmission of Oldowan tool-making skills along chains of adult human participants (N=184) using five different transmission mechanisms. Across six measures, transmission improves with teaching, and particularly with language, but not with imitation or emulation. Our results support the hypothesis that hominin reliance on stone tool-making generated selection for teaching and language, and imply that (i) low-fidelity social transmission, such as imitation/emulation, may have contributed to the ~700,000 year stasis of the Oldowan technocomplex, and (ii) teaching or proto-language may have been pre-requisites for the appearance of Acheulean technology. This work supports a gradual evolution of language, with simple symbolic communication preceding behavioural modernity by hundreds of thousands of years.Modelling prey consumption and switching by UK grey sealshttp://hdl.handle.net/10023/6914
British grey seals (Halichoerus grypus) are adaptable generalist predators whose diet includes commercial fish species such as cod. Consumption by the seals may reduce the abundance of some fish species, and a further concern is that consumption by predators might adversely affect stock recovery programs because predation may trap sparse prey in a ‘predator pit’. The likelihood of these outcomes depends on the way in which consumption (and consequent predation mortality) responds to changes in the availability of prey. We present a model of consumption as a function of prey abundance, which was fitted using data on seal diet and prey availability. Bayesian methodology was employed to account for uncertainties in both dependent and independent variables, improve estimation convergence by the use of informative priors, and allow the estimation of missing prey abundance data. Both Type 1 and Type 2 functional response models were fitted to the data and the Type 2 model was clearly favoured during model selection. The selected model was able to reproduce important contrasts in diet observed in different years and sampling locations.
Wed, 01 Jan 2014 00:00:00 GMThttp://hdl.handle.net/10023/69142014-01-01T00:00:00ZSmout, Sophie CarolineRindorf, AnnaHammond, Philip StevenHarwood, JohnMatthiopoulos, JasonBritish grey seals (Halichoerus grypus) are adaptable generalist predators whose diet includes commercial fish species such as cod. Consumption by the seals may reduce the abundance of some fish species, and a further concern is that consumption by predators might adversely affect stock recovery programs because predation may trap sparse prey in a ‘predator pit’. The likelihood of these outcomes depends on the way in which consumption (and consequent predation mortality) responds to changes in the availability of prey. We present a model of consumption as a function of prey abundance, which was fitted using data on seal diet and prey availability. Bayesian methodology was employed to account for uncertainties in both dependent and independent variables, improve estimation convergence by the use of informative priors, and allow the estimation of missing prey abundance data. Both Type 1 and Type 2 functional response models were fitted to the data and the Type 2 model was clearly favoured during model selection. The selected model was able to reproduce important contrasts in diet observed in different years and sampling locations.Spatial variation in maximum dive depth in gray seals in relation to foraging.http://hdl.handle.net/10023/6886
Habitat preference maps are a way of representing animals’ space use in two dimensions. For marine animals, the third dimension is an important aspect of spatial ecology. We used dive data from seven gray seals Halichoerus grypus (a primarily benthic forager) collected with GPS phone tags (Sea Mammal Research Unit) to investigate the distribution of the maximum depth visited in each dive. We modeled maximum dive depth as a function of spatiotemporal covariates using a generalized additive mixed model (GAMM) with individual as a random effect. Bathymetry, horizontal displacement, latitude and longitude, Julian day, sediment type, and light conditions accounted for 37% of the variability in the data. Persistent patterns of autocorrelation in the raw data suggest that individual intrinsic rhythm might be an important factor, not captured by external covariates. The strength of using this statistical method to generate spatial predictions of the distribution of maximum dive depth is its applicability to other plunge and pursuit divers. Despite being predictions of a point estimate, these maps provide some insight into the third dimension of habitat use in marine animals. The capacity to predict this aspect of vertical habitat use may help avoid conflict between animal habitat and coastal or offshore developments
Theoni Photopoulou was funded by SMRU Ltd in the form of a Ph.D. studentship, 2008–2012.
Tue, 01 Jul 2014 00:00:00 GMThttp://hdl.handle.net/10023/68862014-07-01T00:00:00ZPhotopoulou, TheoniFedak, MikeThomas, LenMatthiopoulos, JasonHabitat preference maps are a way of representing animals’ space use in two dimensions. For marine animals, the third dimension is an important aspect of spatial ecology. We used dive data from seven gray seals Halichoerus grypus (a primarily benthic forager) collected with GPS phone tags (Sea Mammal Research Unit) to investigate the distribution of the maximum depth visited in each dive. We modeled maximum dive depth as a function of spatiotemporal covariates using a generalized additive mixed model (GAMM) with individual as a random effect. Bathymetry, horizontal displacement, latitude and longitude, Julian day, sediment type, and light conditions accounted for 37% of the variability in the data. Persistent patterns of autocorrelation in the raw data suggest that individual intrinsic rhythm might be an important factor, not captured by external covariates. The strength of using this statistical method to generate spatial predictions of the distribution of maximum dive depth is its applicability to other plunge and pursuit divers. Despite being predictions of a point estimate, these maps provide some insight into the third dimension of habitat use in marine animals. The capacity to predict this aspect of vertical habitat use may help avoid conflict between animal habitat and coastal or offshore developmentsFirst indications that northern bottlenose whales are sensitive to behavioural disturbance from anthropogenic noisehttp://hdl.handle.net/10023/6872
Although northern bottlenose whales were the most heavily hunted beaked whale, we have little information about this species in its remote habitat of the North Atlantic Ocean. Underwater anthropogenic noise and disruption of their natural habitat may be major threats, given the sensitivity of other beaked whales to such noise disturbance. We attached dataloggers to 13 northern bottlenose whales and compared their natural sounds and movements to those of one individual exposed to escalating levels of 1–2 kHz upsweep naval sonar signals. At a received sound pressure level (SPL) of 98 dB re 1 μPa, the whale turned to approach the sound source, but at a received SPL of 107 dB re 1 μPa, the whale began moving in an unusually straight course and then made a near 180° turn away from the source, and performed the longest and deepest dive (94 min, 2339 m) recorded for this species. Animal movement parameters differed significantly from baseline for more than 7 h until the tag fell off 33–36 km away. No clicks were emitted during the response period, indicating cessation of normal echolocation-based foraging. A sharp decline in both acoustic and visual detections of conspecifics after exposure suggests other whales in the area responded similarly. Though more data are needed, our results indicate high sensitivity of this species to acoustic disturbance, with consequent risk from marine industrialization and naval activity.
Wed, 03 Jun 2015 00:00:00 GMThttp://hdl.handle.net/10023/68722015-06-03T00:00:00ZMiller, PatrickKvadsheim, P HLam, F P ATyack, Peter LloydCuré, CDe Ruiter, Stacy LynnKleivane, LSivle, L Dvan IJsselmuide, S PVisser, FWensveen, Paulus Jacobusvon Benda-Beckmann, A MMartin Lopez, Lucia MartinaNarazaki, TomokoHooker, Sascha KateAlthough northern bottlenose whales were the most heavily hunted beaked whale, we have little information about this species in its remote habitat of the North Atlantic Ocean. Underwater anthropogenic noise and disruption of their natural habitat may be major threats, given the sensitivity of other beaked whales to such noise disturbance. We attached dataloggers to 13 northern bottlenose whales and compared their natural sounds and movements to those of one individual exposed to escalating levels of 1–2 kHz upsweep naval sonar signals. At a received sound pressure level (SPL) of 98 dB re 1 μPa, the whale turned to approach the sound source, but at a received SPL of 107 dB re 1 μPa, the whale began moving in an unusually straight course and then made a near 180° turn away from the source, and performed the longest and deepest dive (94 min, 2339 m) recorded for this species. Animal movement parameters differed significantly from baseline for more than 7 h until the tag fell off 33–36 km away. No clicks were emitted during the response period, indicating cessation of normal echolocation-based foraging. A sharp decline in both acoustic and visual detections of conspecifics after exposure suggests other whales in the area responded similarly. Though more data are needed, our results indicate high sensitivity of this species to acoustic disturbance, with consequent risk from marine industrialization and naval activity.Conspecific recognition and aggression reduction to familiars in newly weaned, socially plastic mammalshttp://hdl.handle.net/10023/6863
Recognising conspecifics and behaving appropriately towards them is a crucial ability for many species. Grey seals (Halichoerus grypus) show varying capabilities in this regard: mother-pup recognition has been demonstrated in some geographical populations but is absent in others, yet there is evidence that individuals aggregate with prior associates. The recognition capabilities of newly weaned grey seal pups were investigated using class recognition trials within the habituation/dishabituation paradigm. Trials took place in pens, using pairs of individuals that either had previously cohabited (familiar) or that had never met before (stranger). Frequencies of olfactory and visual investigative behaviours (‘checks’) and aggressive interactions were recorded during trials. Familiar individuals recognised each other: paired strangers showed significantly more checks and aggressive interactions than were seen in trials pairing familiars. Oxytocin concentrations in post-trial plasma samples were analysed to investigate the underlying physiology modulating recognition abilities; however, no significant differences were detected between familiar or stranger trials. This study demonstrates that at a young age, grey seals can recognise individuals they have previously encountered. Recognition abilities in this species have adaptive value by allowing the reduction of costly aggressive interactions between familiar conspecifics, which is often cited as the first step towards the evolution of sociality in a species. This study is the first with wild subjects to find conspecific recognition abilities in a pinniped species outside of reproductive contexts. It demonstrates that even largely solitary species can be capable of recognition and pro-social behaviours that benefit them during times when they must aggregate.
This work was conducted as part of a PhD, which was funded by the UK Natural Environment Research Council (NERC) grant NE/H524930/1 and by SMRU Marine, St Andrews, UK.
Sat, 01 Aug 2015 00:00:00 GMThttp://hdl.handle.net/10023/68632015-08-01T00:00:00ZRobinson, Kelly JoanneTwiss, SeanHazon, NeilMoss, SimonLonergan, MikePomeroy, PatrickRecognising conspecifics and behaving appropriately towards them is a crucial ability for many species. Grey seals (Halichoerus grypus) show varying capabilities in this regard: mother-pup recognition has been demonstrated in some geographical populations but is absent in others, yet there is evidence that individuals aggregate with prior associates. The recognition capabilities of newly weaned grey seal pups were investigated using class recognition trials within the habituation/dishabituation paradigm. Trials took place in pens, using pairs of individuals that either had previously cohabited (familiar) or that had never met before (stranger). Frequencies of olfactory and visual investigative behaviours (‘checks’) and aggressive interactions were recorded during trials. Familiar individuals recognised each other: paired strangers showed significantly more checks and aggressive interactions than were seen in trials pairing familiars. Oxytocin concentrations in post-trial plasma samples were analysed to investigate the underlying physiology modulating recognition abilities; however, no significant differences were detected between familiar or stranger trials. This study demonstrates that at a young age, grey seals can recognise individuals they have previously encountered. Recognition abilities in this species have adaptive value by allowing the reduction of costly aggressive interactions between familiar conspecifics, which is often cited as the first step towards the evolution of sociality in a species. This study is the first with wild subjects to find conspecific recognition abilities in a pinniped species outside of reproductive contexts. It demonstrates that even largely solitary species can be capable of recognition and pro-social behaviours that benefit them during times when they must aggregate.Studies for carrying out the common fisheries policy : adverse fisheries impacts on cetacean populations in the Black Sea. Final report to the European Commissionhttp://hdl.handle.net/10023/6856
Mon, 08 Jun 2015 00:00:00 GMThttp://hdl.handle.net/10023/68562015-06-08T00:00:00ZBirkun, AlexeiNorthridge, SimonWillsteed, EdJames, FrancesKilgour, CharlesLander, MartinFitzgerald, GavinAnnual report on the implementation of Council Regulation (EC) No 812/2004 during 2014http://hdl.handle.net/10023/6855
Mon, 01 Jun 2015 00:00:00 GMThttp://hdl.handle.net/10023/68552015-06-01T00:00:00ZNorthridge, SimonKingston, AlThomas, LenModelling harbour seal habitat by combining data from multiple tracking systemshttp://hdl.handle.net/10023/6804
Technological developments over the last 20 years have meant that telemetry studies have used a variety of techniques, each with different levels of accuracy and temporal resolution. This presents a challenge when combining data from these different tracking systems to obtain larger sample sizes or to compare habitat use over time. In this study, we used a Bayesian state-space modelling approach to integrate tracking data from multiple tag types and standardise position estimates while accounting for location error. Harbour seal (Phoca vitulina) telemetry data for the Moray Firth, Scotland, were collated from three tag types: VHF, Argos satellite and GPS–GSM. Tags were deployed on 37 seals during 1989 to 2009 resulting in 37 tracks with a total of 2886 tracking days and a mean duration of 87 days per track. A state-space model was applied to all of the raw tracks to provide daily position estimates and a measure of the uncertainty for each position. We used this standardised tracking dataset to model their habitat use and preference, which was then scaled by the population size estimated from haul-out counts to give an estimate of the absolute number of harbour seals using different parts of the Moray Firth. As expected for a central place forager, harbour seals most frequently occurred in areas close to their inshore haul-out sites. However, our analyses also demonstrated consistent use of offshore foraging grounds, typically within 30 km of haul-out sites in waters < 50 m deep. The use of these statistical models to integrate and compare different datasets is especially important for assessing longer-term responses to environmental variation and anthropogenic activities, allowing management advice to be based upon datasets that integrate information from all available tracking technologies.
This work is supported by the Scottish Government, the Scottish Ofﬁce and the DECC SEA programme.
Wed, 01 Jan 2014 00:00:00 GMThttp://hdl.handle.net/10023/68042014-01-01T00:00:00ZBailey, HelenHammond, Philip StevenThompson, Paul MTechnological developments over the last 20 years have meant that telemetry studies have used a variety of techniques, each with different levels of accuracy and temporal resolution. This presents a challenge when combining data from these different tracking systems to obtain larger sample sizes or to compare habitat use over time. In this study, we used a Bayesian state-space modelling approach to integrate tracking data from multiple tag types and standardise position estimates while accounting for location error. Harbour seal (Phoca vitulina) telemetry data for the Moray Firth, Scotland, were collated from three tag types: VHF, Argos satellite and GPS–GSM. Tags were deployed on 37 seals during 1989 to 2009 resulting in 37 tracks with a total of 2886 tracking days and a mean duration of 87 days per track. A state-space model was applied to all of the raw tracks to provide daily position estimates and a measure of the uncertainty for each position. We used this standardised tracking dataset to model their habitat use and preference, which was then scaled by the population size estimated from haul-out counts to give an estimate of the absolute number of harbour seals using different parts of the Moray Firth. As expected for a central place forager, harbour seals most frequently occurred in areas close to their inshore haul-out sites. However, our analyses also demonstrated consistent use of offshore foraging grounds, typically within 30 km of haul-out sites in waters < 50 m deep. The use of these statistical models to integrate and compare different datasets is especially important for assessing longer-term responses to environmental variation and anthropogenic activities, allowing management advice to be based upon datasets that integrate information from all available tracking technologies.Seasonal variability of the warm Atlantic water layer in the vicinity of the Greenland shelf breakhttp://hdl.handle.net/10023/6801
The warmest water reaching the east and west coast of Greenland is found between 200 m and 600 m. Whilst important for melting Greenland's outlet glaciers, limited winter observations of this layer prohibit determination of its seasonality. To address this, temperature data from Argo profiling floats, a range of sources within the World Ocean Database and unprecedented coverage from marine-mammal borne sensors have been analysed for the period 2002-2011. A significant seasonal range in temperature (~1-2 °C) is found in the warm layer, in contrast to most of the surrounding ocean. The phase of the seasonal cycle exhibits considerable spatial variability, with the warmest water found near the eastern and southwestern shelf-break towards the end of the calendar year. High-resolution ocean model trajectory analysis suggest the timing of the arrival of the year's warmest water is a function of advection time from the subduction site in the Irminger Basin.
This research was funded by the UK Natural Environment Research Council Grant. NE/H01103X/1.
Tue, 16 Dec 2014 00:00:00 GMThttp://hdl.handle.net/10023/68012014-12-16T00:00:00ZGrist, Jeremy P.Josey, Simon A.Boehme, LarsMeredith, Michael P.Laidre, KristinHeide-Jorgensen, Mads PeterKovacs, KitLydersen, ChristianDavidson, FraserStenson, GarryHammill, MikeMarsh, RobertCoward, AndrewThe warmest water reaching the east and west coast of Greenland is found between 200 m and 600 m. Whilst important for melting Greenland's outlet glaciers, limited winter observations of this layer prohibit determination of its seasonality. To address this, temperature data from Argo profiling floats, a range of sources within the World Ocean Database and unprecedented coverage from marine-mammal borne sensors have been analysed for the period 2002-2011. A significant seasonal range in temperature (~1-2 °C) is found in the warm layer, in contrast to most of the surrounding ocean. The phase of the seasonal cycle exhibits considerable spatial variability, with the warmest water found near the eastern and southwestern shelf-break towards the end of the calendar year. High-resolution ocean model trajectory analysis suggest the timing of the arrival of the year's warmest water is a function of advection time from the subduction site in the Irminger Basin.Recommendations for photo-identification methods used in capture-recapture models with cetaceanshttp://hdl.handle.net/10023/6796
Capture-recapture methods are frequently employed to estimate abundance of cetaceans using photographic techniques and a variety of statistical models. However, there are many unresolved issues regarding the selection and manipulation of images that can potentially impose bias on resulting estimates. To examine the potential impact of these issues we circulated a test data set of dorsal fin images from bottlenose dolphins to several independent research groups. Photo-identification methods were generally similar, but the selection, scoring, and matching of images varied greatly amongst groups. Based on these results we make the following recommendations. Researchers should: (1) determine the degree of marking, or level of distinctiveness, and use images of sufficient quality to recognize animals of that level of distinctiveness; (2) ensure that markings are sufficiently distinct to eliminate the potential for “twins” to occur; (3) stratify data sets by distinctiveness and generate a series of abundance estimates to investigate the influence of including animals of varying degrees of markings; and (4) strive to examine and incorporate variability among analysts into capture-recapture estimation. In this paper we summarize these potential sources of bias and provide recommendations for best practices for using natural markings in a capture-recapture framework.
Thu, 01 Jan 2015 00:00:00 GMThttp://hdl.handle.net/10023/67962015-01-01T00:00:00ZUrian, KimGorgone, ARead, Andrew JBalmer, BrianWells, Randall SBerggren, PerDurban, John WEguchi, TomoRayment, WillHammond, Philip StevenCapture-recapture methods are frequently employed to estimate abundance of cetaceans using photographic techniques and a variety of statistical models. However, there are many unresolved issues regarding the selection and manipulation of images that can potentially impose bias on resulting estimates. To examine the potential impact of these issues we circulated a test data set of dorsal fin images from bottlenose dolphins to several independent research groups. Photo-identification methods were generally similar, but the selection, scoring, and matching of images varied greatly amongst groups. Based on these results we make the following recommendations. Researchers should: (1) determine the degree of marking, or level of distinctiveness, and use images of sufficient quality to recognize animals of that level of distinctiveness; (2) ensure that markings are sufficiently distinct to eliminate the potential for “twins” to occur; (3) stratify data sets by distinctiveness and generate a series of abundance estimates to investigate the influence of including animals of varying degrees of markings; and (4) strive to examine and incorporate variability among analysts into capture-recapture estimation. In this paper we summarize these potential sources of bias and provide recommendations for best practices for using natural markings in a capture-recapture framework.Distribution, abundance, and feeding ecology of baleen whales in Icelandic waters: have recent environmental changes had an effect?http://hdl.handle.net/10023/6720
The location of Iceland at the junction of submarine ridges in the North-East Atlantic where warm and cold water masses meet south of the Arctic Circle contributes to high productivity of the waters around the island. During the last two decades, substantial increases in sea temperature and salinity have been reported. Concurrently, pronounced changes have occurred in the distribution of several fish species and euphausiids. The distribution and abundance of cetaceans in the Central and Eastern North Atlantic have been monitored regularly since 1987. Significant changes in the distribution and abundance of several cetacean species have occurred in this time period. The abundance of Central North Atlantic (CNA) humpback and fin whales has increased from 1800 to 11,600 and 15,200 to 20,600, respectively, in the period 1987–2007. In contrast, the abundance of minke whales on the Icelandic continental shelf decreased from around 44,000 in 2001 to 20,000 in 2007 and 10,000 in 2009. The increase in fin whale abundance was accompanied by expansion of distribution into the deep waters of the Irminger Sea. The distribution of the endangered blue whale has shifted northwards in this period. The habitat selection of fin whales was analyzed with respect to physical variables (temperature, depth, salinity) using a generalized additive model, and the results suggest that abundance was influenced by an interaction between the physical variables depth and distance to the 2000 m isobaths, but also by sea surface temperature (SST) and sea surface height (SSH), However, environmental data generally act as proxies of other variables, to which the whales respond directly. Overall, these changes in cetacean distribution and abundance may be a functional feeding response of the cetacean species to physical and biological changes in the marine environment, including decreased abundance of euphausiids, a northward shift in summer distribution of capelin and a crash in the abundance of sand eel.
Date of Acceptance: 13/01/2015
Tue, 17 Feb 2015 00:00:00 GMThttp://hdl.handle.net/10023/67202015-02-17T00:00:00ZVikingsson, Gisli APike, Daniel GValdimarsson, HéðinnSchleimer, AnnaGunnlaugsson, ThorvaldurSilva, TeresaElvarsson, Bjarki ÞMikkelsen, BjarniØien, NilsDesportes, GenevièveBogason, ValurHammond, Philip StevenThe location of Iceland at the junction of submarine ridges in the North-East Atlantic where warm and cold water masses meet south of the Arctic Circle contributes to high productivity of the waters around the island. During the last two decades, substantial increases in sea temperature and salinity have been reported. Concurrently, pronounced changes have occurred in the distribution of several fish species and euphausiids. The distribution and abundance of cetaceans in the Central and Eastern North Atlantic have been monitored regularly since 1987. Significant changes in the distribution and abundance of several cetacean species have occurred in this time period. The abundance of Central North Atlantic (CNA) humpback and fin whales has increased from 1800 to 11,600 and 15,200 to 20,600, respectively, in the period 1987–2007. In contrast, the abundance of minke whales on the Icelandic continental shelf decreased from around 44,000 in 2001 to 20,000 in 2007 and 10,000 in 2009. The increase in fin whale abundance was accompanied by expansion of distribution into the deep waters of the Irminger Sea. The distribution of the endangered blue whale has shifted northwards in this period. The habitat selection of fin whales was analyzed with respect to physical variables (temperature, depth, salinity) using a generalized additive model, and the results suggest that abundance was influenced by an interaction between the physical variables depth and distance to the 2000 m isobaths, but also by sea surface temperature (SST) and sea surface height (SSH), However, environmental data generally act as proxies of other variables, to which the whales respond directly. Overall, these changes in cetacean distribution and abundance may be a functional feeding response of the cetacean species to physical and biological changes in the marine environment, including decreased abundance of euphausiids, a northward shift in summer distribution of capelin and a crash in the abundance of sand eel.Long-term trends in the use of a protected area by small cetaceans in relation to changes in population statushttp://hdl.handle.net/10023/6712
The requirement to monitor listed species in European designated sites is challenging for long-lived mobile species that only temporarily occupy protected areas. We use a 21 year time series of bottlenose dolphin photo-identification data to assess trends in abundance and conservation status within a Special Area of Conservation (SAC) in Scotland. Mark–recapture methods were used to estimate annual abundance within the SAC from 1990 to 2010. A Bayesian mark–recapture model with a state-space approach was used to estimate overall population trends using data collected across the populations’ range. Despite inter-annual variability in the number of dolphins within the SAC, there was a >99% probability that the wider population was stable or increasing. Results indicate that use of the SAC by the wider population has declined. This is the first evidence of long-term trends in the use of an EU protected area by small cetaceans in relation to changes in overall population status. Our results highlight the importance of adapting the survey protocols used in long-term photo-identification studies to maintain high capture probabilities and minimise sampling heterogeneity. Crucially, these data demonstrate the value of collecting data from the wider population to assess the success of protected areas designated for mobile predators.
The BES, ASAB, Greenpeace Environmental Trust, Scottish Natural Heritage, Scottish Government, Whale and Dolphin Conservation, Talisman Energy (UK) Ltd., Department of Energy and Climate Change, Chevron, Natural Environment Research Council (NERC) and the University of Aberdeen all provided funding for annual surveys in the Moray Firth. St. Andrews Bay surveys were funded by a Royal Society University Research Fellowship to V.M.J., studentships from NERC and the Mexican National Council for Science and Technology (CONACYT).
Mon, 01 Dec 2014 00:00:00 GMThttp://hdl.handle.net/10023/67122014-12-01T00:00:00ZCheney, BarbaraCorkery, RossDurban, JohnGrellier, KateHammond, Philip StevenIslas Villanueva, ValentinaJanik, Vincent M.Lusseau, SusanParsons, KimQuick, Nicola JaneWilson, BenThompson, PaulThe requirement to monitor listed species in European designated sites is challenging for long-lived mobile species that only temporarily occupy protected areas. We use a 21 year time series of bottlenose dolphin photo-identification data to assess trends in abundance and conservation status within a Special Area of Conservation (SAC) in Scotland. Mark–recapture methods were used to estimate annual abundance within the SAC from 1990 to 2010. A Bayesian mark–recapture model with a state-space approach was used to estimate overall population trends using data collected across the populations’ range. Despite inter-annual variability in the number of dolphins within the SAC, there was a >99% probability that the wider population was stable or increasing. Results indicate that use of the SAC by the wider population has declined. This is the first evidence of long-term trends in the use of an EU protected area by small cetaceans in relation to changes in overall population status. Our results highlight the importance of adapting the survey protocols used in long-term photo-identification studies to maintain high capture probabilities and minimise sampling heterogeneity. Crucially, these data demonstrate the value of collecting data from the wider population to assess the success of protected areas designated for mobile predators.Echolocation : clicking for supperhttp://hdl.handle.net/10023/6702
When close to prey, porpoises actively widen their sonar beam, which may make it harder for the prey to escape.
Wed, 29 Apr 2015 00:00:00 GMThttp://hdl.handle.net/10023/67022015-04-29T00:00:00ZTyack, Peter LloydWhen close to prey, porpoises actively widen their sonar beam, which may make it harder for the prey to escape.The Argos-CLS Kalman filter : error structures and state-space modelling relative to Fastloc GPS datahttp://hdl.handle.net/10023/6651
Understanding how an animal utilises its surroundings requires its movements through space to be described accurately. Satellite telemetry is the only means of acquiring movement data for many species however data are prone to varying amounts of spatial error; the recent application of state-space models (SSMs) to the location estimation problem have provided a means to incorporate spatial errors when characterising animal movements. The predominant platform for collecting satellite telemetry data on free-ranging animals, Service Argos, recently provided an alternative Doppler location estimation algorithm that is purported to be more accurate and generate a greater number of locations that its predecessor. We provide a comprehensive assessment of this new estimation process performance on data from free-ranging animals relative to concurrently collected Fastloc GPS data. Additionally, we test the efficacy of three readily-available SSM in predicting the movement of two focal animals. Raw Argos location estimates generated by the new algorithm were greatly improved compared to the old system. Approximately twice as many Argos locations were derived compared to GPS on the devices used. Root Mean Square Errors (RMSE) for each optimal SSM were less than 4.25km with some producing RMSE of less than 2.50km. Differences in the biological plausibility of the tracks between the two focal animals used to investigate the utility of SSM highlights the importance of considering animal behaviour in movement studies. The ability to reprocess Argos data collected since 2008 with the new algorithm should permit questions of animal movement to be revisited at a finer resolution.
Funding was provided by the Norwegian Polar Institute centre for Ice, Climate and Ecosystems (ICE).
Thu, 23 Apr 2015 00:00:00 GMThttp://hdl.handle.net/10023/66512015-04-23T00:00:00ZLowther, A.D.Lydersen, C.Fedak, M.A.Lovell, PhilipKovacs, K.M.Understanding how an animal utilises its surroundings requires its movements through space to be described accurately. Satellite telemetry is the only means of acquiring movement data for many species however data are prone to varying amounts of spatial error; the recent application of state-space models (SSMs) to the location estimation problem have provided a means to incorporate spatial errors when characterising animal movements. The predominant platform for collecting satellite telemetry data on free-ranging animals, Service Argos, recently provided an alternative Doppler location estimation algorithm that is purported to be more accurate and generate a greater number of locations that its predecessor. We provide a comprehensive assessment of this new estimation process performance on data from free-ranging animals relative to concurrently collected Fastloc GPS data. Additionally, we test the efficacy of three readily-available SSM in predicting the movement of two focal animals. Raw Argos location estimates generated by the new algorithm were greatly improved compared to the old system. Approximately twice as many Argos locations were derived compared to GPS on the devices used. Root Mean Square Errors (RMSE) for each optimal SSM were less than 4.25km with some producing RMSE of less than 2.50km. Differences in the biological plausibility of the tracks between the two focal animals used to investigate the utility of SSM highlights the importance of considering animal behaviour in movement studies. The ability to reprocess Argos data collected since 2008 with the new algorithm should permit questions of animal movement to be revisited at a finer resolution.Range-dependent flexibility in the acoustic field of view of echolocating porpoises (Phocoena phocoena)http://hdl.handle.net/10023/6646
Toothed whales use sonar to detect, locate, and track prey. They adjust emitted sound intensity, auditory sensitivity and click rate to target range, and terminate prey pursuits with high-repetition-rate, low-intensity buzzes. However, their narrow acoustic field of view (FOV) is considered stable throughout target approach, which could facilitate prey escape at close-range. Here we show that, like some bats, harbour porpoises can broaden their biosonar beam during the terminal phase of attack but, unlike bats, maintain the ability to change beamwidth within this phase. Based on video, MRI, and acoustic-tag recordings, we propose this flexibility is modulated by the melon and implemented to accommodate dynamic spatial relationships with prey and acoustic complexity of surroundings. Despite independent evolution and different means of sound generation and transmission, whales and bats adaptively change their FOV, suggesting that beamwidth flexibility has been an important driver in the evolution of echolocation for prey tracking.
Funding: Det Frie Forskningsrad (MJ)
Fri, 20 Mar 2015 00:00:00 GMThttp://hdl.handle.net/10023/66462015-03-20T00:00:00ZWisniewska, D.M.Ratcliffe, J.M.Beedholm, K.Christensen, C.B.Johnson, MarkKoblitz, J.C.Wahlberg, M.Madsen, P.T.Toothed whales use sonar to detect, locate, and track prey. They adjust emitted sound intensity, auditory sensitivity and click rate to target range, and terminate prey pursuits with high-repetition-rate, low-intensity buzzes. However, their narrow acoustic field of view (FOV) is considered stable throughout target approach, which could facilitate prey escape at close-range. Here we show that, like some bats, harbour porpoises can broaden their biosonar beam during the terminal phase of attack but, unlike bats, maintain the ability to change beamwidth within this phase. Based on video, MRI, and acoustic-tag recordings, we propose this flexibility is modulated by the melon and implemented to accommodate dynamic spatial relationships with prey and acoustic complexity of surroundings. Despite independent evolution and different means of sound generation and transmission, whales and bats adaptively change their FOV, suggesting that beamwidth flexibility has been an important driver in the evolution of echolocation for prey tracking.Using accelerometers to determine the calling behavior of tagged baleen whaleshttp://hdl.handle.net/10023/6623
Low-frequency acoustic signals generated by baleen whales can propagate over vast distances, making the assignment of calls to specific individuals problematic. Here, we report the novel use of acoustic recording tags equipped with high-resolution accelerometers to detect vibrations from the surface of two tagged fin whales that directly match the timing of recorded acoustic signals. A tag deployed on a buoy in the vicinity of calling fin whales and a recording from a tag that had just fallen off a whale were able to detect calls acoustically but did not record corresponding accelerometer signals that were measured on calling individuals. Across the hundreds of calls measured on two tagged fin whales, the accelerometer response was generally anisotropic across all three axes, appeared to depend on tag placement and increased with the level of received sound. These data demonstrate that high-sample rate accelerometry can provide important insights into the acoustic behavior of baleen whales that communicate at low frequencies. This method helps identify vocalizing whales, which in turn enables the quantification of call rates, a fundamental component of models used to estimate baleen whale abundance and distribution from passive acoustic monitoring.
Tue, 15 Jul 2014 00:00:00 GMThttp://hdl.handle.net/10023/66232014-07-15T00:00:00ZGoldbogen, JeremyDe Ruiter, Stacy LynnStimpert, AlisonCalambokidis, JohnFriedlaender, AriSchorr, GregMoretti, DavidTyack, Peter LloydSouthall, BrandonLow-frequency acoustic signals generated by baleen whales can propagate over vast distances, making the assignment of calls to specific individuals problematic. Here, we report the novel use of acoustic recording tags equipped with high-resolution accelerometers to detect vibrations from the surface of two tagged fin whales that directly match the timing of recorded acoustic signals. A tag deployed on a buoy in the vicinity of calling fin whales and a recording from a tag that had just fallen off a whale were able to detect calls acoustically but did not record corresponding accelerometer signals that were measured on calling individuals. Across the hundreds of calls measured on two tagged fin whales, the accelerometer response was generally anisotropic across all three axes, appeared to depend on tag placement and increased with the level of received sound. These data demonstrate that high-sample rate accelerometry can provide important insights into the acoustic behavior of baleen whales that communicate at low frequencies. This method helps identify vocalizing whales, which in turn enables the quantification of call rates, a fundamental component of models used to estimate baleen whale abundance and distribution from passive acoustic monitoring.Adapting to a warmer ocean – seasonal shift of baleen whale movements over three decadeshttp://hdl.handle.net/10023/6290
Global warming poses particular challenges to migratory species, which face changes to the multiple environments occupied during migration. For many species, the timing of migration between summer and winter grounds and also within-season movements are crucial to maximise exploitation of temporarily abundant prey resources in feeding areas, themselves adapting to the warming planet. We investigated the temporal variation in the occurrence of fin (Balaenoptera physalus) and humpback whales (Megaptera novaeangliae) in a North Atlantic summer feeding ground, the Gulf of St. Lawrence (Canada), from 1984 to 2010 using a long-term study of individually identifiable animals. These two sympatric species both shifted their date of arrival at a previously undocumented rate of more than 1day per year earlier over the study period thus maintaining the approximate 2-week difference in arrival of the two species and enabling the maintenance of temporal niche separation. However, the departure date of both species also shifted earlier but at different rates resulting in increasing temporal overlap over the study period indicating that this separation may be starting to erode. Our analysis revealed that the trend in arrival was strongly related to earlier ice break-up and rising sea surface temperature, likely triggering earlier primary production. The observed changes in phenology in response to ocean warming are a remarkable example of phenotypic plasticity and may partly explain how baleen whales were able to survive a number of changes in climate over the last several million years. However, it is questionable whether the observed rate of change in timing can be maintained. Substantial modification to the distribution or annual life cycle of these species might be required to keep up with the ongoing warming of the oceans.
Date of Acceptance: 11/02/2015
Wed, 18 Mar 2015 00:00:00 GMThttp://hdl.handle.net/10023/62902015-03-18T00:00:00ZRamp, ChristianDelarue, JulianPalsbøll, Per JSears, RichardHammond, Philip StevenGlobal warming poses particular challenges to migratory species, which face changes to the multiple environments occupied during migration. For many species, the timing of migration between summer and winter grounds and also within-season movements are crucial to maximise exploitation of temporarily abundant prey resources in feeding areas, themselves adapting to the warming planet. We investigated the temporal variation in the occurrence of fin (Balaenoptera physalus) and humpback whales (Megaptera novaeangliae) in a North Atlantic summer feeding ground, the Gulf of St. Lawrence (Canada), from 1984 to 2010 using a long-term study of individually identifiable animals. These two sympatric species both shifted their date of arrival at a previously undocumented rate of more than 1day per year earlier over the study period thus maintaining the approximate 2-week difference in arrival of the two species and enabling the maintenance of temporal niche separation. However, the departure date of both species also shifted earlier but at different rates resulting in increasing temporal overlap over the study period indicating that this separation may be starting to erode. Our analysis revealed that the trend in arrival was strongly related to earlier ice break-up and rising sea surface temperature, likely triggering earlier primary production. The observed changes in phenology in response to ocean warming are a remarkable example of phenotypic plasticity and may partly explain how baleen whales were able to survive a number of changes in climate over the last several million years. However, it is questionable whether the observed rate of change in timing can be maintained. Substantial modification to the distribution or annual life cycle of these species might be required to keep up with the ongoing warming of the oceans.Humpback whale song on the southern ocean feeding grounds : implications for cultural transmissionhttp://hdl.handle.net/10023/6222
Male humpback whales produce a long, complex, and stereotyped song on low-latitude breeding grounds; they also sing while migrating to and from these locations, and occasionally in high-latitude summer feeding areas. All males in a population sing the current version of the constantly evolving display and, within an ocean basin, populations sing similar songs; however, this sharing can be complex. In the western and central South Pacific region there is repeated cultural transmission of song types from eastern Australia to other populations eastward. Song sharing is hypothesized to occur through several possible mechanisms. Here, we present the first example of feeding ground song from the Southern Ocean Antarctic Area V and compare it to song from the two closest breeding populations. The early 2010 song contained at least four distinct themes; these matched four themes from the eastern Australian 2009 song, and the same four themes from the New Caledonian 2010 song recorded later in the year. This provides evidence for at least one of the hypothesized mechanisms of song transmission between these two populations, singing while on shared summer feeding grounds. In addition, the feeding grounds may provide a point of acoustic contact to allow the rapid horizontal cultural transmission of song within the western and central South Pacific region and the wider Southern Ocean.
Date of Acceptance: 23/09/2013
Wed, 20 Nov 2013 00:00:00 GMThttp://hdl.handle.net/10023/62222013-11-20T00:00:00ZGarland, Ellen C.Gedamke, JasonRekdahl, Melinda L.Noad, Michael J.Garrigue, ClaireGales, NickMale humpback whales produce a long, complex, and stereotyped song on low-latitude breeding grounds; they also sing while migrating to and from these locations, and occasionally in high-latitude summer feeding areas. All males in a population sing the current version of the constantly evolving display and, within an ocean basin, populations sing similar songs; however, this sharing can be complex. In the western and central South Pacific region there is repeated cultural transmission of song types from eastern Australia to other populations eastward. Song sharing is hypothesized to occur through several possible mechanisms. Here, we present the first example of feeding ground song from the Southern Ocean Antarctic Area V and compare it to song from the two closest breeding populations. The early 2010 song contained at least four distinct themes; these matched four themes from the eastern Australian 2009 song, and the same four themes from the New Caledonian 2010 song recorded later in the year. This provides evidence for at least one of the hypothesized mechanisms of song transmission between these two populations, singing while on shared summer feeding grounds. In addition, the feeding grounds may provide a point of acoustic contact to allow the rapid horizontal cultural transmission of song within the western and central South Pacific region and the wider Southern Ocean.Sperm whale response to tag boat presence : biologically informed hidden state models quantify lost feeding opportunitieshttp://hdl.handle.net/10023/6112
Animal-attached sensors provide invaluable data to describe behavior of cryptic species, such as cetaceans, and are increasingly used to assess anthropogenic disturbance effects. Tag deployment and handling may itself alter the behavior of study animals and there is a need to assess if and when behavior recovers to an undisturbed level. Not all behavioral changes have fitness consequences, and our goal is to derive metrics that can be linked to fitness implications, such as time and energy allocation to different functional behaviors. Here we detail an approach that incorporates biological knowledge and multiple streams of tag-recorded data in a hidden state-switching model to estimate time series of functional behavioral st ates for 12 sperm whales off Norway. Foraging, recovery and resting states were specified in the hidden state model by state-dependent likelihood structures. Comparison of hidden state models revealed a parsimonious set of input time series, and supported the inclusion of a less informed 'silent active' state. There was a high agreement between state estimates and expert classifications. We then used the estimated states in time series models to test three hypotheses for behavioral change during suction-cup tag deployment procedures: change in behavioral states, change in prey capture attempts and locomotion cost, given behavioral state. Sperm whales spent 34% less time at the sea surface and 60% more time in non-foraging silent active state in the presence of the tag boat (''tagging period'' 0.1-2.8 h) than during post-tagging baseline period (1.8-20.8 h). No comparable pre-tagging baseline data were available. Nevertheless, time-decaying models of tagging effects were not retained in model selection, indicating a short-term effect that ceased immediately after the tagging period. We did not find changes in energetic proxies, given behavioral state, however changes in functional state budget indicate costs in terms of lost feeding opportunities and recovery time at surface. These results are useful to quantitatively identify data periods that should not be considered baseline behavior within tag recordings. This functional state approach proves effective to quantify disturbance in terms of time and energy allocation that is based upon general principles that can be applied to other species and biologging applications.
The authors acknowledge the UK Ministry of Defence, U.S. Office of Naval Research, and World Wildlife Fund (Norway) for funding this research.
Wed, 21 Jan 2015 00:00:00 GMThttp://hdl.handle.net/10023/61122015-01-21T00:00:00ZIsojunno, S.Miller, P.J.O.Animal-attached sensors provide invaluable data to describe behavior of cryptic species, such as cetaceans, and are increasingly used to assess anthropogenic disturbance effects. Tag deployment and handling may itself alter the behavior of study animals and there is a need to assess if and when behavior recovers to an undisturbed level. Not all behavioral changes have fitness consequences, and our goal is to derive metrics that can be linked to fitness implications, such as time and energy allocation to different functional behaviors. Here we detail an approach that incorporates biological knowledge and multiple streams of tag-recorded data in a hidden state-switching model to estimate time series of functional behavioral st ates for 12 sperm whales off Norway. Foraging, recovery and resting states were specified in the hidden state model by state-dependent likelihood structures. Comparison of hidden state models revealed a parsimonious set of input time series, and supported the inclusion of a less informed 'silent active' state. There was a high agreement between state estimates and expert classifications. We then used the estimated states in time series models to test three hypotheses for behavioral change during suction-cup tag deployment procedures: change in behavioral states, change in prey capture attempts and locomotion cost, given behavioral state. Sperm whales spent 34% less time at the sea surface and 60% more time in non-foraging silent active state in the presence of the tag boat (''tagging period'' 0.1-2.8 h) than during post-tagging baseline period (1.8-20.8 h). No comparable pre-tagging baseline data were available. Nevertheless, time-decaying models of tagging effects were not retained in model selection, indicating a short-term effect that ceased immediately after the tagging period. We did not find changes in energetic proxies, given behavioral state, however changes in functional state budget indicate costs in terms of lost feeding opportunities and recovery time at surface. These results are useful to quantitatively identify data periods that should not be considered baseline behavior within tag recordings. This functional state approach proves effective to quantify disturbance in terms of time and energy allocation that is based upon general principles that can be applied to other species and biologging applications.Measuring acoustic habitatshttp://hdl.handle.net/10023/6087
Many organisms depend on sound for communication, predator/prey detection and navigation. The acoustic environment can therefore play an important role in ecosystem dynamics and evolution. A growing number of studies are documenting acoustic habitats and their influences on animal development, behaviour, physiology and spatial ecology, which has led to increasing demand for passive acoustic monitoring (PAM) expertise in the life sciences. However, as yet, there has been no synthesis of data processing methods for acoustic habitat monitoring, which presents an unnecessary obstacle to would-be PAM analysts. Here, we review the signal processing techniques needed to produce calibrated measurements of terrestrial and aquatic acoustic habitats. We include a supplemental tutorial and template computer codes in matlab and r, which give detailed guidance on how to produce calibrated spectrograms and statistical analyses of sound levels. Key metrics and terminology for the characterisation of biotic, abiotic and anthropogenic sound are covered, and their application to relevant monitoring scenarios is illustrated through example data sets. To inform study design and hardware selection, we also include an up-to-date overview of terrestrial and aquatic PAM instruments. Monitoring of acoustic habitats at large spatiotemporal scales is becoming possible through recent advances in PAM technology. This will enhance our understanding of the role of sound in the spatial ecology of acoustically sensitive species and inform spatial planning to mitigate the rising influence of anthropogenic noise in these ecosystems. As we demonstrate in this work, progress in these areas will depend upon the application of consistent and appropriate PAM methodologies.
NDM was part-funded by an EPSRC Doctoral Training Award (No. EP/P505399/1). MPJ and PLT were supported by Marine Alliance for Science and Technology Scotland (MASTS) and MPJ by a Marie Curie CIG Award.
Sun, 01 Mar 2015 00:00:00 GMThttp://hdl.handle.net/10023/60872015-03-01T00:00:00ZMerchant, N.D.Fristrup, K.M.Johnson, M.P.Tyack, P.L.Witt, M.J.Blondel, P.Parks, S.E.Many organisms depend on sound for communication, predator/prey detection and navigation. The acoustic environment can therefore play an important role in ecosystem dynamics and evolution. A growing number of studies are documenting acoustic habitats and their influences on animal development, behaviour, physiology and spatial ecology, which has led to increasing demand for passive acoustic monitoring (PAM) expertise in the life sciences. However, as yet, there has been no synthesis of data processing methods for acoustic habitat monitoring, which presents an unnecessary obstacle to would-be PAM analysts. Here, we review the signal processing techniques needed to produce calibrated measurements of terrestrial and aquatic acoustic habitats. We include a supplemental tutorial and template computer codes in matlab and r, which give detailed guidance on how to produce calibrated spectrograms and statistical analyses of sound levels. Key metrics and terminology for the characterisation of biotic, abiotic and anthropogenic sound are covered, and their application to relevant monitoring scenarios is illustrated through example data sets. To inform study design and hardware selection, we also include an up-to-date overview of terrestrial and aquatic PAM instruments. Monitoring of acoustic habitats at large spatiotemporal scales is becoming possible through recent advances in PAM technology. This will enhance our understanding of the role of sound in the spatial ecology of acoustically sensitive species and inform spatial planning to mitigate the rising influence of anthropogenic noise in these ecosystems. As we demonstrate in this work, progress in these areas will depend upon the application of consistent and appropriate PAM methodologies.Cetacean morbillivirus : current knowledge and future directionshttp://hdl.handle.net/10023/5996
We review the molecular and epidemiological characteristics of cetacean morbillivirus (CeMV) and the diagnosis and pathogenesis of associated disease, with six different strains detected in cetaceans worldwide. CeMV has caused epidemics with high mortality in odontocetes in Europe, the USAand Australia. It represents a distinct species within the Morbillivirusgenus. Although most CeMV strains are phylogenetically closely related, recent data indicate that morbilliviruses recovered from Indo-Pacific bottlenose dolphins (Tursiops aduncus), from Western Australia, and a Guiana dolphin (Sotalia guianensis), from Brazil, are divergent. The signaling lymphocyte activation molecule (SLAM) cell receptor for CeMV has been characterized in cetaceans. It shares higher amino acid identity with the ruminant SLAM than with the receptors of carnivores or humans, reflecting the evolutionary history of these mammalian taxa. In Delphinidae, three amino acid substitutions may result in a higher affinity for the virus. Infection is diagnosed by histology, immunohistochemistry, virus isolation, RT-PCR, and serology. Classical CeMV-associated lesions include bronchointerstitial pneumonia, encephalitis, syncytia, and lymphoid depletion associated with immunosuppression. Cetaceans that survive the acute disease may develop fatal secondary infections and chronic encephalitis. Endemicallyinfected, gregarious odontocetes probably serve as reservoirs and vectors. Transmission likely occurs through the inhalation of aerosolized virus but mother to fetus transmission was also reported.
Mon, 22 Dec 2014 00:00:00 GMThttp://hdl.handle.net/10023/59962014-12-22T00:00:00ZVan Bressem, M.-F.Duignan, P.J.Banyard, A.Barbieri, M.Colegrove, K.M.de Guise, S.di Guardo, G.Dobson, A.Domingo, M.Fauquier, D.Fernandez, A.Goldstein, T.Grenfell, B.Groch, K.R.Gulland, F.Jensen, B.A.Jepson, P.D.Hall, A.Kuiken, T.Mazzariol, S.Morris, S.E.Nielsen, O.Raga, J.A.Rowles, T.K.Saliki, J.Sierra, E.Stephens, N.Stone, B.Tomo, I.Wang, J.Waltzek, T.Wellehan, J.F.X.We review the molecular and epidemiological characteristics of cetacean morbillivirus (CeMV) and the diagnosis and pathogenesis of associated disease, with six different strains detected in cetaceans worldwide. CeMV has caused epidemics with high mortality in odontocetes in Europe, the USAand Australia. It represents a distinct species within the Morbillivirusgenus. Although most CeMV strains are phylogenetically closely related, recent data indicate that morbilliviruses recovered from Indo-Pacific bottlenose dolphins (Tursiops aduncus), from Western Australia, and a Guiana dolphin (Sotalia guianensis), from Brazil, are divergent. The signaling lymphocyte activation molecule (SLAM) cell receptor for CeMV has been characterized in cetaceans. It shares higher amino acid identity with the ruminant SLAM than with the receptors of carnivores or humans, reflecting the evolutionary history of these mammalian taxa. In Delphinidae, three amino acid substitutions may result in a higher affinity for the virus. Infection is diagnosed by histology, immunohistochemistry, virus isolation, RT-PCR, and serology. Classical CeMV-associated lesions include bronchointerstitial pneumonia, encephalitis, syncytia, and lymphoid depletion associated with immunosuppression. Cetaceans that survive the acute disease may develop fatal secondary infections and chronic encephalitis. Endemicallyinfected, gregarious odontocetes probably serve as reservoirs and vectors. Transmission likely occurs through the inhalation of aerosolized virus but mother to fetus transmission was also reported.Phocine distemper Virus : current knowledge and future directionshttp://hdl.handle.net/10023/5995
Phocine distemper virus (PDV) was first recognized in 1988 following a massive epidemic in harbor and grey seals in north-western Europe. Since then, the epidemiology of infection in North Atlantic and Arctic pinnipeds has been investigated. In the western North Atlantic endemic infection in harp and grey seals predates the European epidemic, with relatively small, localized mortality events occurring primarily in harbor seals. By contrast, PDV seems not to have become established in European harbor seals following the 1988 epidemic and a second event of similar magnitude and extent occurred in 2002. PDV is a distinct species within the Morbillivirus genus with minor sequence variation between outbreaks over time. There is now mounting evidence of PDV-like viruses in the North Pacific/Western Arctic with serological and molecular evidence of infection in pinnipeds and sea otters. However, despite the absence of associated mortality in the region, there is concern that the virus may infect the large Pacific harbor seal and northern elephant seal populations or the endangered Hawaiian monk seals. Here, we review the current state of knowledge on PDV with particular focus on developments in diagnostics, pathogenesis, immune response, vaccine development, phylogenetics and modeling over the past 20 years.
Mon, 22 Dec 2014 00:00:00 GMThttp://hdl.handle.net/10023/59952014-12-22T00:00:00ZDuignan, P.J.Van Bressem, M.-F.Baker, J.D.Barbieri, M.Colegrove, K.M.de Guise, S.de Swart, R.L.di Guardo, G.Dobson, A.Duprex, W.P.Early, G.Fauquier, D.Goldstein, T.Goodman, S.J.Grenfell, B.Groch, K.R.Gulland, F.Hall, A.Jensen, B.A.Lamy, K.Matassa, K.Mazzariol, S.Morris, S.E.Nielsen, O.Rotstein, D.Rowles, T.K.Saliki, J.T.Siebert, U.Waltzek, T.Wellehan, J.F.Phocine distemper virus (PDV) was first recognized in 1988 following a massive epidemic in harbor and grey seals in north-western Europe. Since then, the epidemiology of infection in North Atlantic and Arctic pinnipeds has been investigated. In the western North Atlantic endemic infection in harp and grey seals predates the European epidemic, with relatively small, localized mortality events occurring primarily in harbor seals. By contrast, PDV seems not to have become established in European harbor seals following the 1988 epidemic and a second event of similar magnitude and extent occurred in 2002. PDV is a distinct species within the Morbillivirus genus with minor sequence variation between outbreaks over time. There is now mounting evidence of PDV-like viruses in the North Pacific/Western Arctic with serological and molecular evidence of infection in pinnipeds and sea otters. However, despite the absence of associated mortality in the region, there is concern that the virus may infect the large Pacific harbor seal and northern elephant seal populations or the endangered Hawaiian monk seals. Here, we review the current state of knowledge on PDV with particular focus on developments in diagnostics, pathogenesis, immune response, vaccine development, phylogenetics and modeling over the past 20 years.A comparison of gridded sea surface temperature datasets for marine ecosystem studieshttp://hdl.handle.net/10023/5878
In assessing impacts of a changing environment on the structure and functioning of marine ecosystems, the challenge remains to distinguish the effects of noise and of temporal and spatial autocorrelation from environmental drivers of biotic change. One analytical approach is to de-trend the data and use the resulting residuals; an alternative method involves use of the raw anomalies and a reduction of the degrees of freedom (df) to make the hypothesis testing more conservative. Here, we assess the comparability of 3 gridded sea surface temperature (SST) datasets—ERSST V3b, HadISST, and OISST V2—to in situ measurements. The 1° gridded HadISST and OISST V2 showed the highest similarity, while the weaker correlations with ERSST V3b probably are attributable to its coarser 2° grid. We investigated the performance of 2 commonly applied statistical methods to resolving autocorrelation, and proceeded to correlation analyses between the SST datasets and 2 contemporaneous 15 yr time-series of the somatic growth condition of annual cohorts of Atlantic salmon Salmo salar, which migrate to the Norwegian Sea. For these latter analyses, reducing df could not fully resolve the problem of high positive autocorrelation. The 3 oceanographic datasets do not provide the same correlative outcomes and levels of significance with the salmon time-series. When analysing time-series that pre-date the availability of satellite data, the choice of dataset is restricted to either ERSST V3b or HadISST; but for recent studies (1982 onwards) OISST V2 also is available, and it will be important to assess the relative merits of the 3 SST data sources when interpreting contrasting correlative outcomes.
The authors acknowledge the support of the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland) in the completion of this study (grant reference HR09011).
Wed, 03 Dec 2014 00:00:00 GMThttp://hdl.handle.net/10023/58782014-12-03T00:00:00ZBoehme, LarsLonergan, MikeTodd, Christopher DavidIn assessing impacts of a changing environment on the structure and functioning of marine ecosystems, the challenge remains to distinguish the effects of noise and of temporal and spatial autocorrelation from environmental drivers of biotic change. One analytical approach is to de-trend the data and use the resulting residuals; an alternative method involves use of the raw anomalies and a reduction of the degrees of freedom (df) to make the hypothesis testing more conservative. Here, we assess the comparability of 3 gridded sea surface temperature (SST) datasets—ERSST V3b, HadISST, and OISST V2—to in situ measurements. The 1° gridded HadISST and OISST V2 showed the highest similarity, while the weaker correlations with ERSST V3b probably are attributable to its coarser 2° grid. We investigated the performance of 2 commonly applied statistical methods to resolving autocorrelation, and proceeded to correlation analyses between the SST datasets and 2 contemporaneous 15 yr time-series of the somatic growth condition of annual cohorts of Atlantic salmon Salmo salar, which migrate to the Norwegian Sea. For these latter analyses, reducing df could not fully resolve the problem of high positive autocorrelation. The 3 oceanographic datasets do not provide the same correlative outcomes and levels of significance with the salmon time-series. When analysing time-series that pre-date the availability of satellite data, the choice of dataset is restricted to either ERSST V3b or HadISST; but for recent studies (1982 onwards) OISST V2 also is available, and it will be important to assess the relative merits of the 3 SST data sources when interpreting contrasting correlative outcomes.Grey seals use anthropogenic signals from acoustic tags to locate fish : evidence from a simulated foraging taskhttp://hdl.handle.net/10023/5800
Anthropogenic noise can have negative effects on animal behaviour and physiology. However, noise is often introduced systematically and potentially provides information for navigation or prey detection. Here, we show that grey seals (Halichoerus grypus) learn to use sounds from acoustic fish tags as an indicator of food location. In 20 randomized trials each, 10 grey seals individually explored 20 foraging boxes, with one box containing a tagged fish, one containing an untagged fish and all other boxes being empty. The tagged box was found after significantly fewer non-tag box visits across trials, and seals revisited boxes containing the tag more often than any other box. The time and number of boxes needed to find both fish decreased significantly throughout consecutive trials. Two additional controls were conducted to investigate the role of the acoustic signal: (i) tags were placed in one box, with no fish present in any boxes and (ii) additional pieces of fish, inaccessible to the seal, were placed in the previously empty 18 boxes, making possible alternative chemosensory cues less reliable. During these controls, the acoustically tagged box was generally found significantly faster than the control box. Our results show that animals learn to use information provided by anthropogenic signals to enhance foraging success.
This study was conducted under Home Office licence number 60/3303
Wed, 07 Jan 2015 00:00:00 GMThttp://hdl.handle.net/10023/58002015-01-07T00:00:00ZStansbury, AmandaGotz, ThomasDeecke, Volker BerntJanik, Vincent M.Anthropogenic noise can have negative effects on animal behaviour and physiology. However, noise is often introduced systematically and potentially provides information for navigation or prey detection. Here, we show that grey seals (Halichoerus grypus) learn to use sounds from acoustic fish tags as an indicator of food location. In 20 randomized trials each, 10 grey seals individually explored 20 foraging boxes, with one box containing a tagged fish, one containing an untagged fish and all other boxes being empty. The tagged box was found after significantly fewer non-tag box visits across trials, and seals revisited boxes containing the tag more often than any other box. The time and number of boxes needed to find both fish decreased significantly throughout consecutive trials. Two additional controls were conducted to investigate the role of the acoustic signal: (i) tags were placed in one box, with no fish present in any boxes and (ii) additional pieces of fish, inaccessible to the seal, were placed in the previously empty 18 boxes, making possible alternative chemosensory cues less reliable. During these controls, the acoustically tagged box was generally found significantly faster than the control box. Our results show that animals learn to use information provided by anthropogenic signals to enhance foraging success.Drag of suction cup tags on swimming animals : modeling and measurementhttp://hdl.handle.net/10023/5799
Bio-logging tags are widely used to study the behavior and movements of marine mammals with the tacit assumption of little impact to the animal. However, tags on fast-swimming animals generate substantial hydrodynamic forces potentially affecting behavior and energetics adversely, or promoting early removal of the tag. In this work, hydrodynamic loading of three novel tag housing designs are compared over a range of swimming speeds using computational fluid dynamics (CFD). Results from CFD simulation were verified using tag models in a water flume with close agreement. Drag forces were reduced by minimizing geometric disruptions to the flow around the housing, while lift forces were reduced by minimizing the frontal cross-sectional area of the housing and holding the tag close to the attachment surface. Hydrodynamic tag design resulted in an experimentally measured 60% drag force reduction in 5.6 m/s flow. For all housing designs, off-axis flow increased the magnitude of the force on the tag. Experimental work with a common dolphin (Delphinus delphis) cadaver indicates that the suction cups used to attach the types of tags described here provide sufficient attachment force to resist failure to predicted forces at swimming speeds of up to 10 m/s.
This work was supported by NOPP with NSF funds through ONR Grant N00014-11-1-0113. MJ was supported by NOPP and the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland). MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions.
Tue, 01 Apr 2014 00:00:00 GMThttp://hdl.handle.net/10023/57992014-04-01T00:00:00ZShorter, K. AlexMurray, Mark M.Johnson, MarkMoore, MichaelHowle, Laurens E.Bio-logging tags are widely used to study the behavior and movements of marine mammals with the tacit assumption of little impact to the animal. However, tags on fast-swimming animals generate substantial hydrodynamic forces potentially affecting behavior and energetics adversely, or promoting early removal of the tag. In this work, hydrodynamic loading of three novel tag housing designs are compared over a range of swimming speeds using computational fluid dynamics (CFD). Results from CFD simulation were verified using tag models in a water flume with close agreement. Drag forces were reduced by minimizing geometric disruptions to the flow around the housing, while lift forces were reduced by minimizing the frontal cross-sectional area of the housing and holding the tag close to the attachment surface. Hydrodynamic tag design resulted in an experimentally measured 60% drag force reduction in 5.6 m/s flow. For all housing designs, off-axis flow increased the magnitude of the force on the tag. Experimental work with a common dolphin (Delphinus delphis) cadaver indicates that the suction cups used to attach the types of tags described here provide sufficient attachment force to resist failure to predicted forces at swimming speeds of up to 10 m/s.Evidence for a genetic basis of urogenital carcinoma in the wild California sea lionhttp://hdl.handle.net/10023/5777
Although neoplasia is a major cause of mortality in humans and domestic animals, it has rarely been described in wildlife species. One of the fewexamples is a highly prevalent urogenital carcinoma in California sea lions (CSLs). Although the aetiology of this carcinoma is clearly multifactorial, inbreeding depression, as estimated using levels of microsatellite multilocus heterozygosity, is identified as predictive for this neoplasia. On further analysis, this relationship appears to be largely driven by one marker, suggesting that a single locus might be associated with the occurrence of this disease in CSLs. In a case–control study, carcinoma was significantly associated with homozygosity at the Pv11 microsatellite locus. Pv11 was mapped to intron 9 of the heparanase 2 gene (HPSE2) locus, a very large gene encoding heparanase 2, which in humans is associated with multiple carcinomas. Correspondingly, immunohistochemical labelling in tissues was present in carcinoma cases within a single homozygous Pv11 genotype. To our knowledge, this is the first report of an individual locus being associated with cancer in any wildlife species. This adds emphasis to the study of HPSE2 in other species, including humans and will guide future studies on this sentinel species that shares much of its diet and environment with humans
This work was funded by a grant from the US National Marine Fisheries Service John H. Prescott Marine Mammal Rescue Assistance grant programme, and H.M.B. was funded by a UK Natural Environment Research Council PhD studentship. J.A.H. was funded by the BBSRC Institute Strategic Programme on Livestock Viral Diseases at The Pirbright Institute.
Mon, 01 Dec 2014 00:00:00 GMThttp://hdl.handle.net/10023/57772014-12-01T00:00:00ZBrowning, Helen M.Acevedo-Whitehouse, KarinaGulland, Frances M. D.Hall, Ailsa J.Finlayson, JeanieDagleish, Mark P.Billington, Karen J.Colegrove, KathleenHammond, John A.Although neoplasia is a major cause of mortality in humans and domestic animals, it has rarely been described in wildlife species. One of the fewexamples is a highly prevalent urogenital carcinoma in California sea lions (CSLs). Although the aetiology of this carcinoma is clearly multifactorial, inbreeding depression, as estimated using levels of microsatellite multilocus heterozygosity, is identified as predictive for this neoplasia. On further analysis, this relationship appears to be largely driven by one marker, suggesting that a single locus might be associated with the occurrence of this disease in CSLs. In a case–control study, carcinoma was significantly associated with homozygosity at the Pv11 microsatellite locus. Pv11 was mapped to intron 9 of the heparanase 2 gene (HPSE2) locus, a very large gene encoding heparanase 2, which in humans is associated with multiple carcinomas. Correspondingly, immunohistochemical labelling in tissues was present in carcinoma cases within a single homozygous Pv11 genotype. To our knowledge, this is the first report of an individual locus being associated with cancer in any wildlife species. This adds emphasis to the study of HPSE2 in other species, including humans and will guide future studies on this sentinel species that shares much of its diet and environment with humansMarine mammals trace anthropogenic structures at seahttp://hdl.handle.net/10023/5560
On land, species from all trophic levels have adapted to fill vacant niches in environments heavily modified by humans (e.g. [1]). In the marine environment, ocean infrastructure has led to artificial reefs, resulting in localized increases in fish and crustacean density [2]. Whether marine apex predators exhibit behavioural adaptations to utilise such a scattered potential resource is unknown. Using high resolution GPS data we show how infrastructure, including wind turbines and pipelines, shapes the movements of individuals from two seal species (Phoca vitulina and Halichoerus grypus). Using state-space models, we infer that these animals are using structures to forage. We highlight the ecological consequences of such behaviour, at a time of unprecedented developments in marine infrastructure.
D.J.F.R., G.H., V.M.J., S.E.W.M. and B.M. were funded by the UK Department of Energy and Climate Change (DECC) as part of their Offshore Energy Strategic Environmental Assessment programme. The tags and their deployment were funded by GSP, NUON, RWE, Eneco and Gemini, DECC, Natural Environment Research Council, Scottish Natural Heritage and Marine Scotland.
Mon, 21 Jul 2014 00:00:00 GMThttp://hdl.handle.net/10023/55602014-07-21T00:00:00ZRussell, Deborah Jill FraserBrasseur, SophieThompson, DavidHastie, Gordon DrummondJanik, Vincent M.Aarts, GeertMcClintock, Brett ThomasMatthiopoulos, JasonMoss, SimonMcConnell, Bernie JOn land, species from all trophic levels have adapted to fill vacant niches in environments heavily modified by humans (e.g. [1]). In the marine environment, ocean infrastructure has led to artificial reefs, resulting in localized increases in fish and crustacean density [2]. Whether marine apex predators exhibit behavioural adaptations to utilise such a scattered potential resource is unknown. Using high resolution GPS data we show how infrastructure, including wind turbines and pipelines, shapes the movements of individuals from two seal species (Phoca vitulina and Halichoerus grypus). Using state-space models, we infer that these animals are using structures to forage. We highlight the ecological consequences of such behaviour, at a time of unprecedented developments in marine infrastructure.Beyond climate envelopes : bio-climate modelling accords with observed 25-year changes in seabird populations of the British Isleshttp://hdl.handle.net/10023/5547
Aim Climate envelope models (CEMs) are used to assess species’ vulnerability to predicted changes in climate, based on their distributions. Extinction risk, however, also depends on demographic parameters. Accordingly, we use CEMs for 18 seabird species to test three hypotheses: (i) population sizes are larger in areas where CEMs fitted using distribution data predict more suitable climate; (ii) the presence of this relationship (Hypothesis i) is related to a species’ foraging ecology; and (iii) species whose distributions and population sizes conformed most closely to indices of climatic suitability in the mid-1980s experienced the largest population changes following climatic change between 1986 and 2010. Location Europe. Methods Climate envelope models fitted at a 50-km resolution using European climatic and distribution data were applied using local climatic data to calculate local climatic suitability indices (CSIs) for 18 species within the British Isles. We then investigated the relationship between CSI and population size at a 10-km resolution and related both the presence of this relationship and goodness-of-fit metrics from the European models to changes in population size (1986–2010). Results Local population sizes were significantly positively related to local CSI in 50% of species, providing support for Hypothesis (i), and these 50% of species were independently considered to be most vulnerable to changes in food availability at sea in support of Hypothesis (ii). Those species whose distributions and populations most closely conformed to indices of climatic suitability showed the least favourable subsequent changes in population size, over a period in which mean climatic suitability decreased for all species, in support of Hypothesis (iii). Main conclusions Climate influences the population sizes of multiple seabird species in the British Isles. We highlight the potential for outputs of CEMs fitted with coarse resolution occupancy data to provide information on both local abundance and sensitivity to future climate changes.
DJFR was supported by the NERC UKPopNet, and BJA was also supported by NERC.
Sun, 01 Feb 2015 00:00:00 GMThttp://hdl.handle.net/10023/55472015-02-01T00:00:00ZRussell, Deborah Jill FraserWanless, SarahCollingham, YvonneAnderson, BarbaraBeale, ColinReid, JamesHuntley, BrianHamer, KeithAim Climate envelope models (CEMs) are used to assess species’ vulnerability to predicted changes in climate, based on their distributions. Extinction risk, however, also depends on demographic parameters. Accordingly, we use CEMs for 18 seabird species to test three hypotheses: (i) population sizes are larger in areas where CEMs fitted using distribution data predict more suitable climate; (ii) the presence of this relationship (Hypothesis i) is related to a species’ foraging ecology; and (iii) species whose distributions and population sizes conformed most closely to indices of climatic suitability in the mid-1980s experienced the largest population changes following climatic change between 1986 and 2010. Location Europe. Methods Climate envelope models fitted at a 50-km resolution using European climatic and distribution data were applied using local climatic data to calculate local climatic suitability indices (CSIs) for 18 species within the British Isles. We then investigated the relationship between CSI and population size at a 10-km resolution and related both the presence of this relationship and goodness-of-fit metrics from the European models to changes in population size (1986–2010). Results Local population sizes were significantly positively related to local CSI in 50% of species, providing support for Hypothesis (i), and these 50% of species were independently considered to be most vulnerable to changes in food availability at sea in support of Hypothesis (ii). Those species whose distributions and populations most closely conformed to indices of climatic suitability showed the least favourable subsequent changes in population size, over a period in which mean climatic suitability decreased for all species, in support of Hypothesis (iii). Main conclusions Climate influences the population sizes of multiple seabird species in the British Isles. We highlight the potential for outputs of CEMs fitted with coarse resolution occupancy data to provide information on both local abundance and sensitivity to future climate changes.Classification of large acoustic datasets using machine learning and crowdsourcing : application to whale callshttp://hdl.handle.net/10023/5353
Vocal communication is a primary communication method of killer and pilot whales, and is used for transmitting a broad range of messages and information for short and long distance. The large variation in call types of these species makes it challenging to categorize them. In this study, sounds recorded by audio sensors carried by ten killer whales and eight pilot whales close to the coasts of Norway, Iceland, and the Bahamas were analyzed using computer methods and citizen scientists as part of the Whale FM project. Results show that the computer analysis automatically separated the killer whales into Icelandic and Norwegian whales, and the pilot whales were separated into Norwegian long-finned and Bahamas short-finned pilot whales, showing that at least some whales from these two locations have different acoustic repertoires that can be sensed by the computer analysis. The citizen science analysis was also able to separate the whales to locations by their sounds, but the separation was somewhat less accurate compared to the computer method.
A.M.v.B.B. acknowledges support from the Sea Mammal Research Unit at the University of St. Andrews (Professor Ian Boyd) and Woods Hole Oceanographic Institution for the Whale FM project. P.T. received funding from the Marine Alliance for Science and Technology for Scotland (MASTS).
Wed, 01 Jan 2014 00:00:00 GMThttp://hdl.handle.net/10023/53532014-01-01T00:00:00ZShamir, L.Yerby, C.Simpson, R.Von Benda-Beckmann, A.M.Tyack, P.Samarra, F.Miller, P.Wallin, J.Vocal communication is a primary communication method of killer and pilot whales, and is used for transmitting a broad range of messages and information for short and long distance. The large variation in call types of these species makes it challenging to categorize them. In this study, sounds recorded by audio sensors carried by ten killer whales and eight pilot whales close to the coasts of Norway, Iceland, and the Bahamas were analyzed using computer methods and citizen scientists as part of the Whale FM project. Results show that the computer analysis automatically separated the killer whales into Icelandic and Norwegian whales, and the pilot whales were separated into Norwegian long-finned and Bahamas short-finned pilot whales, showing that at least some whales from these two locations have different acoustic repertoires that can be sensed by the computer analysis. The citizen science analysis was also able to separate the whales to locations by their sounds, but the separation was somewhat less accurate compared to the computer method.Drift diving by hooded seals (Cystophora cristata) in the Northwest Atlantic Oceanhttp://hdl.handle.net/10023/5278
Many pinniped species perform a specific dive type, referred to as a ‘drift dive’, where they drift passively through the water column. This dive type has been suggested to function as a resting/sleeping or food processing dive, and can be used as an indication of feeding success by calculating the daily change in vertical drift rates over time, which reflects the relative fluctuations in buoyancy of the animal as the proportion of lipids in the body change. Northwest Atlantic hooded seals perform drift dives at regular intervals throughout their annual migration across the Northwest Atlantic Ocean. We found that the daily change in drift rate varied with geographic location and the time of year and that this differed between sexes. Positive changes in buoyancy (reflecting increased lipid stores) were evident throughout their migration range and although overlapping somewhat, they were not statistically associated with high use areas as indicated by First Passage Time (FPT). Differences in the seasonal fluctuations of buoyancy between males and females suggest that they experience a difference in patterns of energy gain and loss during winter and spring, associated with breeding. The fluctuations in buoyancy around the moulting period were similar between sexes.
This work was funded through the Atlantic Seal Research Programme, International Governance Programme (GBS and MOH), the Greenland Institute of Natural Resources (ARA), and a CFI grant to YFW. The authors also acknowledge the support of the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland) in the completion of this study. MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions (LB).
Tue, 22 Jul 2014 00:00:00 GMThttp://hdl.handle.net/10023/52782014-07-22T00:00:00ZAndersen, JulieStenson, GarrySkern-Maurizen, MetteWiersma, YolandaRosing-Asvid, AqqaluBoehme, LarsHammill, MikeMany pinniped species perform a specific dive type, referred to as a ‘drift dive’, where they drift passively through the water column. This dive type has been suggested to function as a resting/sleeping or food processing dive, and can be used as an indication of feeding success by calculating the daily change in vertical drift rates over time, which reflects the relative fluctuations in buoyancy of the animal as the proportion of lipids in the body change. Northwest Atlantic hooded seals perform drift dives at regular intervals throughout their annual migration across the Northwest Atlantic Ocean. We found that the daily change in drift rate varied with geographic location and the time of year and that this differed between sexes. Positive changes in buoyancy (reflecting increased lipid stores) were evident throughout their migration range and although overlapping somewhat, they were not statistically associated with high use areas as indicated by First Passage Time (FPT). Differences in the seasonal fluctuations of buoyancy between males and females suggest that they experience a difference in patterns of energy gain and loss during winter and spring, associated with breeding. The fluctuations in buoyancy around the moulting period were similar between sexes.The effects of acoustic misclassification on cetacean species abundance estimationhttp://hdl.handle.net/10023/5163
To estimate the density or abundance of a cetacean species using acoustic detection data, it is necessary to correctly identify the species that are detected. Developing an automated species classifier with 100% correct classification rate for any species is likely to stay out of reach. It is therefore necessary to consider the effect of misidentified detections on the number of observed data and consequently on abundance or density estimation, and develop methods to cope with these misidentifications. If misclassification rates are known, it is possible to estimate the true numbers of detected calls without bias. However, misclassification and uncertainties in the level of misclassification increase the variance of the estimates. If the true numbers of calls from different species are similar, then a small amount of misclassification between species and a small amount of uncertainty around the classification probabilities does not have an overly detrimental effect on the overall variance. However, if there is a difference in the encounter rate between species calls and/or a large amount of uncertainty in misclassification rates, then the variance of the estimates becomes very large and this dramatically increases the variance of the final abundance estimate.
This work was funded through the Natural Environment Research Council and SMRU Ltd.
Wed, 25 Dec 2013 00:00:00 GMThttp://hdl.handle.net/10023/51632013-12-25T00:00:00ZCaillat, Marjolaine AnnieThomas, LenGillespie, Douglas MichaelTo estimate the density or abundance of a cetacean species using acoustic detection data, it is necessary to correctly identify the species that are detected. Developing an automated species classifier with 100% correct classification rate for any species is likely to stay out of reach. It is therefore necessary to consider the effect of misidentified detections on the number of observed data and consequently on abundance or density estimation, and develop methods to cope with these misidentifications. If misclassification rates are known, it is possible to estimate the true numbers of detected calls without bias. However, misclassification and uncertainties in the level of misclassification increase the variance of the estimates. If the true numbers of calls from different species are similar, then a small amount of misclassification between species and a small amount of uncertainty around the classification probabilities does not have an overly detrimental effect on the overall variance. However, if there is a difference in the encounter rate between species calls and/or a large amount of uncertainty in misclassification rates, then the variance of the estimates becomes very large and this dramatically increases the variance of the final abundance estimate.Dose-response relationships for the onset of avoidance of sonar by free-ranging killer whaleshttp://hdl.handle.net/10023/5092
Eight experimentally controlled exposures to 1−2 kHz or 6−7 kHz sonar signals were conducted with four killer whale groups. The source level and proximity of the source were increased during each exposure in order to reveal response thresholds. Detailed inspection of movements during each exposure session revealed sustained changes in speed and travel direction judged to be avoidance responses during six of eight sessions. Following methods developed for Phase-I clinical trials in human medicine, response thresholds ranging from 94 to 164 dB re 1 μPa received sound pressure level (SPL) were fitted to Bayesian dose-response functions. Thresholds did not consistently differ by sonar frequency or whether a group had previously been exposed, with a mean SPL response threshold of 142 ± 15 dB (mean ± s.d.). High levels of between- and within-individual variability were identified, indicating that thresholds depended upon other undefined contextual variables. The dose-response functions indicate that some killer whales started to avoid sonar at received SPL below thresholds assumed by the U.S. Navy. The predicted extent of habitat over which avoidance reactions occur depends upon whether whales responded to proximity or received SPL of the sonar or both, but was large enough to raise concerns about biological consequences to the whales.
The authors acknowledge the support of the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland) in the completion of this study. MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions.
Sat, 01 Feb 2014 00:00:00 GMThttp://hdl.handle.net/10023/50922014-02-01T00:00:00ZMiller, PatrickAntunes, Ricardo NunoWensveen, Paulus JacobusSamarra, Filipa Isabel PereiraAlves, Ana Catarina De CarvalhoTyack, Peter LloydKvadsheim, Petter H.Kleivane, LarsLam, Frans-Peter A.Ainslie, Michael A.Thomas, LenEight experimentally controlled exposures to 1−2 kHz or 6−7 kHz sonar signals were conducted with four killer whale groups. The source level and proximity of the source were increased during each exposure in order to reveal response thresholds. Detailed inspection of movements during each exposure session revealed sustained changes in speed and travel direction judged to be avoidance responses during six of eight sessions. Following methods developed for Phase-I clinical trials in human medicine, response thresholds ranging from 94 to 164 dB re 1 μPa received sound pressure level (SPL) were fitted to Bayesian dose-response functions. Thresholds did not consistently differ by sonar frequency or whether a group had previously been exposed, with a mean SPL response threshold of 142 ± 15 dB (mean ± s.d.). High levels of between- and within-individual variability were identified, indicating that thresholds depended upon other undefined contextual variables. The dose-response functions indicate that some killer whales started to avoid sonar at received SPL below thresholds assumed by the U.S. Navy. The predicted extent of habitat over which avoidance reactions occur depends upon whether whales responded to proximity or received SPL of the sonar or both, but was large enough to raise concerns about biological consequences to the whales.Trackline and point detection probabilities for acoustic surveys of Cuvier’s and Blainville’s beaked whaleshttp://hdl.handle.net/10023/5091
Acoustic survey methods can be used to estimate density and abundance using sounds produced by cetaceans and detected using hydrophones if the probability of detection can be estimated. For passive acoustic surveys, probability of detection at zero horizontal distance from a sensor, commonly called g(0), depends on the temporal patterns of vocalizations. Methods to estimate g(0) are developed based on the assumption that a beaked whale will be detected if it is producing regular echolocation clicks directly under or above a hydrophone. Data from acoustic recording tags placed on two species of beaked whales (Cuvier’s beaked whale—Ziphius cavirostris and Blainville’s beaked whale—Mesoplodon densirostris) are used to directly estimate the percentage of time they produce echolocation clicks. A model of vocal behavior for these species as a function of their diving behavior is applied to other types of dive data (from time-depth recorders and time-depth-transmitting satellite tags) to indirectly determine g(0) in other locations for low ambient noise conditions. Estimates of g(0) for a single instant in time are 0.28 [standard deviation (s.d.) ¼ 0.05] for Cuvier’s beaked whale and 0.19 (s.d. ¼ 0.01) for Blainville’s beaked whale.
Fri, 01 Feb 2013 00:00:00 GMThttp://hdl.handle.net/10023/50912013-02-01T00:00:00ZBarlow, JayTyack, Peter LloydJohnson, Mark JBaird, Robin WSchorr, Greg SAndrews, Russ Dde Soto, Natacha AguilarAcoustic survey methods can be used to estimate density and abundance using sounds produced by cetaceans and detected using hydrophones if the probability of detection can be estimated. For passive acoustic surveys, probability of detection at zero horizontal distance from a sensor, commonly called g(0), depends on the temporal patterns of vocalizations. Methods to estimate g(0) are developed based on the assumption that a beaked whale will be detected if it is producing regular echolocation clicks directly under or above a hydrophone. Data from acoustic recording tags placed on two species of beaked whales (Cuvier’s beaked whale—Ziphius cavirostris and Blainville’s beaked whale—Mesoplodon densirostris) are used to directly estimate the percentage of time they produce echolocation clicks. A model of vocal behavior for these species as a function of their diving behavior is applied to other types of dive data (from time-depth recorders and time-depth-transmitting satellite tags) to indirectly determine g(0) in other locations for low ambient noise conditions. Estimates of g(0) for a single instant in time are 0.28 [standard deviation (s.d.) ¼ 0.05] for Cuvier’s beaked whale and 0.19 (s.d. ¼ 0.01) for Blainville’s beaked whale.Effective beam pattern of the Blainville's beaked whale (Mesoplodon densirostris) and implications for passive acoustic monitoringhttp://hdl.handle.net/10023/5090
The presence of beaked whales in mass-strandings coincident with navy maneuvers has prompted the development of methods to detect these cryptic animals. Blainville's beaked whales, Mesoplodon densirostris, produce distinctive echolocation clicks during long foraging dives making passive acoustic detection a possibility. However, performance of passive acoustic monitoring depends upon the source level, beam pattern, and clicking behavior of the whales. In this study, clicks recorded from Digital acoustic Tags (DTags) attached to four M. densirostris were linked to simultaneous recordings from an 82-hydrophone bottom-mounted array to derive the source level and beam pattern of the clicks, as steps towards estimating their detectability. The mean estimated on-axis apparent source level for the four whales was 201 dB(rms97). The mean 3 dB beamwidth and directivity index, estimated from sequences of clicks directed towards the far-field hydrophones, were 13 degrees and 23 dB, respectively. While searching for prey, Blainville's beaked whales scan their heads horizontally at a mean rate of 3.6 degrees/s over an angular range of some +/-10 degrees. Thus, while the DI indicates a narrow beam, the area of ensonification over a complete foraging dive is large given the combined effects of body and head movements associated with foraging. [http://dx.doi.org/10.1121/1.4776177]
This work was funded by two partners under the National Oceanographic Partnership Program: the Ocean Acoustics Program of the U.S. National Marine Fisheries Service, Office of Protected Resources, and the International Association of Oil and Gas Producers Joint Industry Programme on Exploration and Production Sound and Marine Life. Research permits were issued to John Boreman (US NMFS 1121-1900), Peter Tyack (US NMFS 981-1578), and Ian Boyd (Bahamas permit #02/07). M.J. and P.T. are supported by the Marine Alliance for Science and Technology Scotland.
Fri, 01 Mar 2013 00:00:00 GMThttp://hdl.handle.net/10023/50902013-03-01T00:00:00ZShaffer, Jessica WardMoretti, DavidJarvis, SusanTyack, PeterJohnson, MarkThe presence of beaked whales in mass-strandings coincident with navy maneuvers has prompted the development of methods to detect these cryptic animals. Blainville's beaked whales, Mesoplodon densirostris, produce distinctive echolocation clicks during long foraging dives making passive acoustic detection a possibility. However, performance of passive acoustic monitoring depends upon the source level, beam pattern, and clicking behavior of the whales. In this study, clicks recorded from Digital acoustic Tags (DTags) attached to four M. densirostris were linked to simultaneous recordings from an 82-hydrophone bottom-mounted array to derive the source level and beam pattern of the clicks, as steps towards estimating their detectability. The mean estimated on-axis apparent source level for the four whales was 201 dB(rms97). The mean 3 dB beamwidth and directivity index, estimated from sequences of clicks directed towards the far-field hydrophones, were 13 degrees and 23 dB, respectively. While searching for prey, Blainville's beaked whales scan their heads horizontally at a mean rate of 3.6 degrees/s over an angular range of some +/-10 degrees. Thus, while the DI indicates a narrow beam, the area of ensonification over a complete foraging dive is large given the combined effects of body and head movements associated with foraging. [http://dx.doi.org/10.1121/1.4776177]SC/65a/E04-Assessing the population consequences of pollutant exposure in cetaceans (Pollution 2000+)-from ingestion to outcomehttp://hdl.handle.net/10023/5086
Tue, 01 Jan 2013 00:00:00 GMThttp://hdl.handle.net/10023/50862013-01-01T00:00:00ZHall, Ailsa JaneHabitat fragmentation and species extirpation in freshwater ecosystems; causes of range decline of the indus river dolphin (Platanista gangetica minor)http://hdl.handle.net/10023/5063
Habitat fragmentation of freshwater ecosystems is increasing rapidly, however the understanding of extinction debt and species decline in riverine habitat fragments lags behind that in other ecosystems. The mighty rivers that drain the Himalaya - the Ganges, Brahmaputra, Indus, Mekong and Yangtze - are amongst the world's most biodiverse freshwater ecosystems. Many hundreds of dams have been constructed, are under construction, or are planned on these rivers and large hydrological changes and losses of biodiversity have occurred and are expected to continue. This study examines the causes of range decline of the Indus dolphin, which inhabits one of the world's most modified rivers, to demonstrate how we may expect other vertebrate populations to respond as planned dams and water developments come into operation. The historical range of the Indus dolphin has been fragmented into 17 river sections by diversion dams; dolphin sighting and interview surveys show that river dolphins have been extirpated from ten river sections, they persist in 6, and are of unknown status in one section. Seven potential factors influencing the temporal and spatial pattern of decline were considered in three regression model sets. Low dry-season river discharge, due to water abstraction at irrigation barrages, was the principal factor that explained the dolphin's range decline, influencing 1) the spatial pattern of persistence, 2) the temporal pattern of subpopulation extirpation, and 3) the speed of extirpation after habitat fragmentation. Dolphins were more likely to persist in the core of the former range because water diversions are concentrated near the range periphery. Habitat fragmentation and degradation of the habitat were inextricably intertwined and in combination caused the catastrophic decline of the Indus dolphin.
World Wildlife Fund-Pakistan -(http://www.wwfpak.org/) funded the interview surveys with support through the Pakistan Wetlands Project. The US Marine Mammal Commission (www.mmc.gov) provided funding to GB for reporting and analysis in grant number E4047595.
Wed, 16 Jul 2014 00:00:00 GMThttp://hdl.handle.net/10023/50632014-07-16T00:00:00ZBraulik, G.T.Arshad, M.Noureen, U.Northridge, S.P.Habitat fragmentation of freshwater ecosystems is increasing rapidly, however the understanding of extinction debt and species decline in riverine habitat fragments lags behind that in other ecosystems. The mighty rivers that drain the Himalaya - the Ganges, Brahmaputra, Indus, Mekong and Yangtze - are amongst the world's most biodiverse freshwater ecosystems. Many hundreds of dams have been constructed, are under construction, or are planned on these rivers and large hydrological changes and losses of biodiversity have occurred and are expected to continue. This study examines the causes of range decline of the Indus dolphin, which inhabits one of the world's most modified rivers, to demonstrate how we may expect other vertebrate populations to respond as planned dams and water developments come into operation. The historical range of the Indus dolphin has been fragmented into 17 river sections by diversion dams; dolphin sighting and interview surveys show that river dolphins have been extirpated from ten river sections, they persist in 6, and are of unknown status in one section. Seven potential factors influencing the temporal and spatial pattern of decline were considered in three regression model sets. Low dry-season river discharge, due to water abstraction at irrigation barrages, was the principal factor that explained the dolphin's range decline, influencing 1) the spatial pattern of persistence, 2) the temporal pattern of subpopulation extirpation, and 3) the speed of extirpation after habitat fragmentation. Dolphins were more likely to persist in the core of the former range because water diversions are concentrated near the range periphery. Habitat fragmentation and degradation of the habitat were inextricably intertwined and in combination caused the catastrophic decline of the Indus dolphin.An alternative method for correcting fluorescence quenchinghttp://hdl.handle.net/10023/5042
Under high light intensity, phytoplankton protect their photosystems from bleaching through non-photochemical quenching processes. The consequence of this is suppression of fluorescence emission, which must be corrected when measuring in situ yield with fluorometers. We present data from the Southern Ocean, collected over five austral summers by 19 southern elephant seals tagged with fluorometers. Conventionally, fluorescence data collected during the day (quenched) were corrected using the limit of the mixed layer, assuming that phytoplankton are uniformly mixed from the surface to this depth. However, distinct deep fluorescence maxima were measured in approximately 30% of the night (unquenched) data. To account for the evidence that chlorophyll is not uniformly mixed in the upper layer, we propose correcting from the limit of the euphotic zone, defined as the depth at which photosynthetically available radiation is ~ 1% of the surface value. Mixed layer depth exceeded euphotic depth over 80% of the time. Under these conditions, quenching was corrected from the depth of the remotely derived euphotic zone Zeu, and compared with fluorescence corrected from the depth of the density-derived mixed layer. Deep fluorescence maxima were evident in only 10% of the day data when correcting from mixed layer depth. This was doubled to 21% when correcting from Zeu, more closely matching the unquenched (night) data. Furthermore, correcting from Zeu served to conserve non-uniform chlorophyll features found between the 1% light level and mixed layer depth.
This work received funding from the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland) and their support is gratefully acknowledged. MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions.
Tue, 13 Jan 2015 00:00:00 GMThttp://hdl.handle.net/10023/50422015-01-13T00:00:00ZBiermann, LaurenGuinet, ChristopheBester, MarthanBrierley, Andrew StuartBoehme, LarsUnder high light intensity, phytoplankton protect their photosystems from bleaching through non-photochemical quenching processes. The consequence of this is suppression of fluorescence emission, which must be corrected when measuring in situ yield with fluorometers. We present data from the Southern Ocean, collected over five austral summers by 19 southern elephant seals tagged with fluorometers. Conventionally, fluorescence data collected during the day (quenched) were corrected using the limit of the mixed layer, assuming that phytoplankton are uniformly mixed from the surface to this depth. However, distinct deep fluorescence maxima were measured in approximately 30% of the night (unquenched) data. To account for the evidence that chlorophyll is not uniformly mixed in the upper layer, we propose correcting from the limit of the euphotic zone, defined as the depth at which photosynthetically available radiation is ~ 1% of the surface value. Mixed layer depth exceeded euphotic depth over 80% of the time. Under these conditions, quenching was corrected from the depth of the remotely derived euphotic zone Zeu, and compared with fluorescence corrected from the depth of the density-derived mixed layer. Deep fluorescence maxima were evident in only 10% of the day data when correcting from mixed layer depth. This was doubled to 21% when correcting from Zeu, more closely matching the unquenched (night) data. Furthermore, correcting from Zeu served to conserve non-uniform chlorophyll features found between the 1% light level and mixed layer depth.Neutral buoyancy is optimal to minimize the cost of transport in horizontally swimming sealshttp://hdl.handle.net/10023/5009
Flying and terrestrial animals should spend energy to move while supporting their weight against gravity. On the other hand, supported by buoyancy, aquatic animals can minimize the energy cost for supporting their body weight and neutral buoyancy has been considered advantageous for aquatic animals. However, some studies suggested that aquatic animals might use non-neutral buoyancy for gliding and thereby save energy cost for locomotion. We manipulated the body density of seals using detachable weights and floats, and compared stroke efforts of horizontally swimming seals under natural conditions using animal-borne recorders. The results indicated that seals had smaller stroke efforts to swim a given speed when they were closer to neutral buoyancy. We conclude that neutral buoyancy is likely the best body density to minimize the cost of transport in horizontal swimming by seals.
This study was supported by National Environment Research Council grant NERC NE/c00311X/1, a Grant-in-Aid for Science Research from the Japan Society for the Promotion of Science (to K.S. and Y.Y.W.), a grant from Canon Foundation and program Bio-Logging Science of the University of Tokyo (UTBLS).
Tue, 16 Jul 2013 00:00:00 GMThttp://hdl.handle.net/10023/50092013-07-16T00:00:00ZSato, KatsufumiAoki, KagariWatanabe, Yuuki Y.Miller, Patrick J. O.Flying and terrestrial animals should spend energy to move while supporting their weight against gravity. On the other hand, supported by buoyancy, aquatic animals can minimize the energy cost for supporting their body weight and neutral buoyancy has been considered advantageous for aquatic animals. However, some studies suggested that aquatic animals might use non-neutral buoyancy for gliding and thereby save energy cost for locomotion. We manipulated the body density of seals using detachable weights and floats, and compared stroke efforts of horizontally swimming seals under natural conditions using animal-borne recorders. The results indicated that seals had smaller stroke efforts to swim a given speed when they were closer to neutral buoyancy. We conclude that neutral buoyancy is likely the best body density to minimize the cost of transport in horizontal swimming by seals.How man-made interference might cause gas bubble emboli in deep diving whaleshttp://hdl.handle.net/10023/4972
Recent cetacean mass strandings in close temporal and spatial association with sonar activity has raised the concern that anthropogenic sound may harm breath-hold diving marine mammals. Necropsy results of the stranded whales have shown evidence of bubbles in the tissues, similar to those in human divers suffering from decompression sickness (DCS). It has been proposed that changes in behavior or physiological responses during diving could increase tissue and blood N2 levels, thereby increasing DCS risk. Dive data recorded from sperm, killer, long-finned pilot, Blainville's beaked and Cuvier's beaked whales before and during exposure to low- (1–2 kHz) and mid- (2–7 kHz) frequency active sonar were used to estimate the changes in blood and tissue N2 tension (PN2). Our objectives were to determine if differences in (1) dive behavior or (2) physiological responses to sonar are plausible risk factors for bubble formation. The theoretical estimates indicate that all species may experience high N2 levels. However, unexpectedly, deep diving generally result in higher end-dive PN2 as compared with shallow diving. In this focused review we focus on three possible explanations: (1) We revisit an old hypothesis that CO2, because of its much higher diffusivity, forms bubble precursors that continue to grow in N2 supersaturated tissues. Such a mechanism would be less dependent on the alveolar collapse depth but affected by elevated levels of CO2 following a burst of activity during sonar exposure. (2) During deep dives, a greater duration of time might be spent at depths where gas exchange continues as compared with shallow dives. The resulting elevated levels of N2 in deep diving whales might also make them more susceptible to anthropogenic disturbances. (3) Extended duration of dives even at depths beyond where the alveoli collapse could result in slow continuous accumulation of N2 in the adipose tissues that eventually becomes a liability.
Tue, 28 Jan 2014 00:00:00 GMThttp://hdl.handle.net/10023/49722014-01-28T00:00:00ZFahlman, AndreasTyack, Peter LloydMiller, PatrickKvadsheim, PetterRecent cetacean mass strandings in close temporal and spatial association with sonar activity has raised the concern that anthropogenic sound may harm breath-hold diving marine mammals. Necropsy results of the stranded whales have shown evidence of bubbles in the tissues, similar to those in human divers suffering from decompression sickness (DCS). It has been proposed that changes in behavior or physiological responses during diving could increase tissue and blood N2 levels, thereby increasing DCS risk. Dive data recorded from sperm, killer, long-finned pilot, Blainville's beaked and Cuvier's beaked whales before and during exposure to low- (1–2 kHz) and mid- (2–7 kHz) frequency active sonar were used to estimate the changes in blood and tissue N2 tension (PN2). Our objectives were to determine if differences in (1) dive behavior or (2) physiological responses to sonar are plausible risk factors for bubble formation. The theoretical estimates indicate that all species may experience high N2 levels. However, unexpectedly, deep diving generally result in higher end-dive PN2 as compared with shallow diving. In this focused review we focus on three possible explanations: (1) We revisit an old hypothesis that CO2, because of its much higher diffusivity, forms bubble precursors that continue to grow in N2 supersaturated tissues. Such a mechanism would be less dependent on the alveolar collapse depth but affected by elevated levels of CO2 following a burst of activity during sonar exposure. (2) During deep dives, a greater duration of time might be spent at depths where gas exchange continues as compared with shallow dives. The resulting elevated levels of N2 in deep diving whales might also make them more susceptible to anthropogenic disturbances. (3) Extended duration of dives even at depths beyond where the alveoli collapse could result in slow continuous accumulation of N2 in the adipose tissues that eventually becomes a liability.Framework for assessing impacts of pile-driving noise from offshore wind farm construction on a harbour seal populationhttp://hdl.handle.net/10023/4774
Offshore wind farm developments may impact protected marine mammal populations, requiring appropriate assessment under the EU Habitats Directive. We describe a framework developed to assess population level impacts of disturbance from piling noise on a protected harbour seal population in the vicinity of proposed wind farm developments in NE Scotland. Spatial patterns of seal distribution and received noise levels are integrated with available data on the potential impacts of noise to predict how many individuals are displaced or experience auditory injury. Expert judgement is used to link these impacts to changes in vital rates and applied to population models that compare population changes under baseline and construction scenarios over a 25. year period. We use published data and hypothetical piling scenarios to illustrate how the assessment framework has been used to support environmental assessments, explore the sensitivity of the framework to key assumptions, and discuss its potential application to other populations of marine mammals.
This work was supported by Moray Offshore Renewables Ltd. and Beatrice Offshore Wind Ltd. as part of their consent application.
Fri, 01 Nov 2013 00:00:00 GMThttp://hdl.handle.net/10023/47742013-11-01T00:00:00ZThompson, P.M.Hastie, G.D.Nedwell, J.Barham, R.Brookes, K.L.Cordes, Line S.Bailey, H.McLean, NancyOffshore wind farm developments may impact protected marine mammal populations, requiring appropriate assessment under the EU Habitats Directive. We describe a framework developed to assess population level impacts of disturbance from piling noise on a protected harbour seal population in the vicinity of proposed wind farm developments in NE Scotland. Spatial patterns of seal distribution and received noise levels are integrated with available data on the potential impacts of noise to predict how many individuals are displaced or experience auditory injury. Expert judgement is used to link these impacts to changes in vital rates and applied to population models that compare population changes under baseline and construction scenarios over a 25. year period. We use published data and hypothetical piling scenarios to illustrate how the assessment framework has been used to support environmental assessments, explore the sensitivity of the framework to key assumptions, and discuss its potential application to other populations of marine mammals.An approximate Bayesian method applied to estimating the trajectories of four British grey seal (Halichoerus grypus) populations from pup counts.http://hdl.handle.net/10023/4688
1. For British grey seals, as with many pinniped species, population monitoring is implemented by aerial surveys of pups at breeding colonies. Scaling pup counts up to population estimates requires assumptions about population structure; this is straightforward when populations are growing exponentially, but not when growth slows, since it is unclear whether density dependence affects pup survival or fecundity. 2. We present an approximate Bayesian method for fitting pup trajectories, estimating adult population size and investigating alternative biological models. The method is equivalent to fitting a density dependent Leslie matrix model, within a Bayesian framework, but with the forms of the density dependent effects as outputs rather than assumptions. 3. This approach requires fewer assumptions than the state space models currently used, and produces similar estimates. The simplifications made the models easier to fit, reducing their computational intensity and allowing regional differences in demographic parameters to be considered. 4. The approach is not restricted to situations where only a single component of the population is observable, but, particularly in those cases, provides a practical method for extracting information from limited datasets. 5. We discuss the potential and limitations of the method and suggest that this approach provides a useful tool for at least the preliminary analysis of similar datasets.
Sat, 01 Jan 2011 00:00:00 GMThttp://hdl.handle.net/10023/46882011-01-01T00:00:00ZLonergan, Michael EdwardThompson, DavidThomas, Leonard JosephDuck, Callan David1. For British grey seals, as with many pinniped species, population monitoring is implemented by aerial surveys of pups at breeding colonies. Scaling pup counts up to population estimates requires assumptions about population structure; this is straightforward when populations are growing exponentially, but not when growth slows, since it is unclear whether density dependence affects pup survival or fecundity. 2. We present an approximate Bayesian method for fitting pup trajectories, estimating adult population size and investigating alternative biological models. The method is equivalent to fitting a density dependent Leslie matrix model, within a Bayesian framework, but with the forms of the density dependent effects as outputs rather than assumptions. 3. This approach requires fewer assumptions than the state space models currently used, and produces similar estimates. The simplifications made the models easier to fit, reducing their computational intensity and allowing regional differences in demographic parameters to be considered. 4. The approach is not restricted to situations where only a single component of the population is observable, but, particularly in those cases, provides a practical method for extracting information from limited datasets. 5. We discuss the potential and limitations of the method and suggest that this approach provides a useful tool for at least the preliminary analysis of similar datasets.Immune activity, body condition and human-associated environmental impacts in a wild marine mammalhttp://hdl.handle.net/10023/4587
Within individuals, immunity may compete with other life history traits for resources, such as energy and protein, and the damage caused by immunopathology can sometimes outweigh the protective benefits that immune responses confer. However, our understanding of the costs of immunity in the wild and how they relate to the myriad energetic demands on free-ranging organisms is limited. The endangered Galapagos sea lion (Zalophus wollebaeki) is threatened simultaneously by disease from domestic animals and rapid changes in food availability driven by unpredictable environmental variation. We made use of this unique ecology to investigate the relationship between changes in immune activity and changes in body condition. We found that during the first three months of life, changes in antibody concentration were negatively correlated with changes in mass per unit length, skinfold thickness and serum albumin concentration, but only in a sea lion colony exposed to anthropogenic environmental impacts. It has previously been shown that changes in antibody concentration during early Galapagos sea lion development were higher in a colony exposed to anthropogenic environmental impacts than in a control colony. This study allows for the possibility that these relatively large changes in antibody concentration are associated with negative impacts on fitness through an effect on body condition. Our findings suggest that energy availability and the degree of plasticity in immune investment may influence disease risk in natural populations synergistically, through a trade-off between investment in immunity and resistance to starvation. The relative benefits of such investments may change quickly and unpredictably, which allows for the possibility that individuals fine-tune their investment strategies in response to changes in environmental conditions. In addition, our results suggest that anthropogenic environmental impacts may impose subtle energetic costs on individuals, which could contribute to population declines, especially in times of energy shortage.
PMB was funded by the Natural Environment Research Council (www.nerc.ac.uk), the Universities Federation for Animal Welfare (www.ufaw.org.uk) and the Sea Mammal Research Unit (www.smru.st-and.ac.uk). The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript.
Tue, 01 Jan 2013 00:00:00 GMThttp://hdl.handle.net/10023/45872013-01-01T00:00:00ZBrock, Patrick MHall, Ailsa JGoodman, Simon JCruz, MarilynAcevedo-Whitehouse, KarinaWithin individuals, immunity may compete with other life history traits for resources, such as energy and protein, and the damage caused by immunopathology can sometimes outweigh the protective benefits that immune responses confer. However, our understanding of the costs of immunity in the wild and how they relate to the myriad energetic demands on free-ranging organisms is limited. The endangered Galapagos sea lion (Zalophus wollebaeki) is threatened simultaneously by disease from domestic animals and rapid changes in food availability driven by unpredictable environmental variation. We made use of this unique ecology to investigate the relationship between changes in immune activity and changes in body condition. We found that during the first three months of life, changes in antibody concentration were negatively correlated with changes in mass per unit length, skinfold thickness and serum albumin concentration, but only in a sea lion colony exposed to anthropogenic environmental impacts. It has previously been shown that changes in antibody concentration during early Galapagos sea lion development were higher in a colony exposed to anthropogenic environmental impacts than in a control colony. This study allows for the possibility that these relatively large changes in antibody concentration are associated with negative impacts on fitness through an effect on body condition. Our findings suggest that energy availability and the degree of plasticity in immune investment may influence disease risk in natural populations synergistically, through a trade-off between investment in immunity and resistance to starvation. The relative benefits of such investments may change quickly and unpredictably, which allows for the possibility that individuals fine-tune their investment strategies in response to changes in environmental conditions. In addition, our results suggest that anthropogenic environmental impacts may impose subtle energetic costs on individuals, which could contribute to population declines, especially in times of energy shortage.Validation of an enzyme-linked immunoassay (ELISA) for plasma oxytocin in a novel mammal species reveals potential errors induced by sampling procedurehttp://hdl.handle.net/10023/4541
BACKGROUND: The neuropeptide oxytocin is increasing the focus of many studies investigating human and animal social behaviours and diseases. However, interpretation and comparison of results is made difficult by a lack of consistent methodological approaches towards analysing this hormone. NEW METHOD: This study determined the sample collection and analysis protocols that cause the least amounts of protocol dependant variation in plasma oxytocin concentrations detected by ELISA. The effect of vacutainer type, sample extraction prior to analysis and capture and restraint protocol were investigated while validating an assay protocol for two novel species, grey seals (Halichoerus grypus) and harbour seals (Phoca vitulina). RESULTS: Where samples are extracted prior to analysis, vacutainer type (EDTA mean: 8.25±0.56pg/ml, heparin mean: 8.25±0.62pg/ml, p=0.82), time taken to obtain a sample and restraint protocol did not affect the concentration of oxytocin detected. However, concentrations of oxytocin detected in raw plasma samples were significantly higher than those in extracted samples, and varied significantly with vacutainer type (EDTA mean: 534.4±43.7pg/ml, heparin mean: 300.9±19.6pg/ml, p<0.001) and capture and restraint methodology. There was no relationship between oxytocin concentrations detected in raw and extracted plasma (p=0.25). COMPARISON WITH EXISTING METHOD(S): Over half the reviewed published studies analysing plasma oxytocin use raw plasma and different vacutainer types are used without consistency or justification through-out the literature. CONCLUSIONS: We caution that studies using raw plasma are likely to over estimate oxytocin concentrations, cannot be used to accurately infer true values via correlations and are susceptible to variation according vacutainer type.
This work was conducted as part of a PhD, which was funded by the Natural Environment Research Council (NERC), UK and by SMRU Marine, St Andrews, UK.
Wed, 01 Jan 2014 00:00:00 GMThttp://hdl.handle.net/10023/45412014-01-01T00:00:00ZRobinson, Kelly JoanneHazon, NeilLonergan, MikePomeroy, PatrickBACKGROUND: The neuropeptide oxytocin is increasing the focus of many studies investigating human and animal social behaviours and diseases. However, interpretation and comparison of results is made difficult by a lack of consistent methodological approaches towards analysing this hormone. NEW METHOD: This study determined the sample collection and analysis protocols that cause the least amounts of protocol dependant variation in plasma oxytocin concentrations detected by ELISA. The effect of vacutainer type, sample extraction prior to analysis and capture and restraint protocol were investigated while validating an assay protocol for two novel species, grey seals (Halichoerus grypus) and harbour seals (Phoca vitulina). RESULTS: Where samples are extracted prior to analysis, vacutainer type (EDTA mean: 8.25±0.56pg/ml, heparin mean: 8.25±0.62pg/ml, p=0.82), time taken to obtain a sample and restraint protocol did not affect the concentration of oxytocin detected. However, concentrations of oxytocin detected in raw plasma samples were significantly higher than those in extracted samples, and varied significantly with vacutainer type (EDTA mean: 534.4±43.7pg/ml, heparin mean: 300.9±19.6pg/ml, p<0.001) and capture and restraint methodology. There was no relationship between oxytocin concentrations detected in raw and extracted plasma (p=0.25). COMPARISON WITH EXISTING METHOD(S): Over half the reviewed published studies analysing plasma oxytocin use raw plasma and different vacutainer types are used without consistency or justification through-out the literature. CONCLUSIONS: We caution that studies using raw plasma are likely to over estimate oxytocin concentrations, cannot be used to accurately infer true values via correlations and are susceptible to variation according vacutainer type.Assessing performance of Bayesian state-space models fit to Argos Satellite telemetry locations processed with Kalman Filteringhttp://hdl.handle.net/10023/4538
Argos recently implemented a new algorithm to calculate locations of satellite-tracked animals that uses a Kalman filter (KF). The KF algorithm is reported to increase the number and accuracy of estimated positions over the traditional Least Squares (LS) algorithm, with potential advantages to the application of state-space methods to model animal movement data. We tested the performance of two Bayesian state-space models (SSMs) fitted to satellite tracking data processed with KF algorithm. Tracks from 7 harbour seals (Phoca vitulina) tagged with ARGOS satellite transmitters equipped with Fastloc GPS loggers were used to calculate the error of locations estimated from SSMs fitted to KF and LS data, by comparing those to “true” GPS locations. Data on 6 fin whales (Balaenoptera physalus) were used to investigate consistency in movement parameters, location and behavioural states estimated by switching state-space models (SSSM) fitted to data derived from KF and LS methods. The model fit to KF locations improved the accuracy of seal trips by 27% over the LS model. 82% of locations predicted from the KF model and 73% of locations from the LS model were <5 km from the corresponding interpolated GPS position. Uncertainty in KF model estimates (5.6±5.6 km) was nearly half that of LS estimates (11.6±8.4 km). Accuracy of KF and LS modelled locations was sensitive to precision but not to observation frequency or temporal resolution of raw Argos data. On average, 88% of whale locations estimated by KF models fell within the 95% probability ellipse of paired locations from LS models. Precision of KF locations for whales was generally higher. Whales’ behavioural mode inferred by KF models matched the classification from LS models in 94% of the cases. State-space models fit to KF data can improve spatial accuracy of location estimates over LS models and produce equally reliable behavioural estimates.
Thu, 20 Mar 2014 00:00:00 GMThttp://hdl.handle.net/10023/45382014-03-20T00:00:00ZSilva, Monica A.Jonsen, IanRussell, Deborah Jill FraserPrieto, RuiThompson, DavidBaumgartner, Mark F.Argos recently implemented a new algorithm to calculate locations of satellite-tracked animals that uses a Kalman filter (KF). The KF algorithm is reported to increase the number and accuracy of estimated positions over the traditional Least Squares (LS) algorithm, with potential advantages to the application of state-space methods to model animal movement data. We tested the performance of two Bayesian state-space models (SSMs) fitted to satellite tracking data processed with KF algorithm. Tracks from 7 harbour seals (Phoca vitulina) tagged with ARGOS satellite transmitters equipped with Fastloc GPS loggers were used to calculate the error of locations estimated from SSMs fitted to KF and LS data, by comparing those to “true” GPS locations. Data on 6 fin whales (Balaenoptera physalus) were used to investigate consistency in movement parameters, location and behavioural states estimated by switching state-space models (SSSM) fitted to data derived from KF and LS methods. The model fit to KF locations improved the accuracy of seal trips by 27% over the LS model. 82% of locations predicted from the KF model and 73% of locations from the LS model were <5 km from the corresponding interpolated GPS position. Uncertainty in KF model estimates (5.6±5.6 km) was nearly half that of LS estimates (11.6±8.4 km). Accuracy of KF and LS modelled locations was sensitive to precision but not to observation frequency or temporal resolution of raw Argos data. On average, 88% of whale locations estimated by KF models fell within the 95% probability ellipse of paired locations from LS models. Precision of KF locations for whales was generally higher. Whales’ behavioural mode inferred by KF models matched the classification from LS models in 94% of the cases. State-space models fit to KF data can improve spatial accuracy of location estimates over LS models and produce equally reliable behavioural estimates.Pup mortality in a rapidly declining harbour seal (Phoca vitulina) populationhttp://hdl.handle.net/10023/4451
The harbour seal population in Orkney, off the north coast of Scotland, has reduced by 65% between 2001 and 2010. The cause(s) of this decline are unknown but must affect the demographic parameters of the population. Here, satellite telemetry data were used to test the hypothesis that increased pup mortality could be a primary driver of the decline in Orkney. Pup mortality and tag failure parameters were estimated from the duration of operation of atellite tags deployed on harbour seal pups from the Orkney population (n = 4) and from another population on the west coast of Scotland (n = 24) where abundance was stable. Survival probabilities from both populations were best represented by a common gamma distribution and were not different from one another, suggesting that increased pup mortality is unlikely to be the primary agent in the Orkney population decline. The estimated probability of surviving to 6 months was 0.390 (95% CI 0.297 – 0.648) and tag failure was represented by a Gaussian distribution, with estimated mean 270 (95% CI = 198 – 288) and s.d. 21 (95% CI = 1 – 66) days. These results suggest that adult survival is the most likely proximate cause of the decline. They also demonstrate a novel technique for attaining age-specific mortality rates from telemetry data.
This research was funded by the Scottish Government (www.scotland.gov.uk), Scottish Natural Heritage (www.snh.gov.uk) and the Natural Environment Research Council (www.nerc.ac.uk). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Wed, 27 Nov 2013 00:00:00 GMThttp://hdl.handle.net/10023/44512013-11-27T00:00:00ZHanson, Nora NellThompson, DavidDuck, Callan DavidMoss, SimonLonergan, MikeThe harbour seal population in Orkney, off the north coast of Scotland, has reduced by 65% between 2001 and 2010. The cause(s) of this decline are unknown but must affect the demographic parameters of the population. Here, satellite telemetry data were used to test the hypothesis that increased pup mortality could be a primary driver of the decline in Orkney. Pup mortality and tag failure parameters were estimated from the duration of operation of atellite tags deployed on harbour seal pups from the Orkney population (n = 4) and from another population on the west coast of Scotland (n = 24) where abundance was stable. Survival probabilities from both populations were best represented by a common gamma distribution and were not different from one another, suggesting that increased pup mortality is unlikely to be the primary agent in the Orkney population decline. The estimated probability of surviving to 6 months was 0.390 (95% CI 0.297 – 0.648) and tag failure was represented by a Gaussian distribution, with estimated mean 270 (95% CI = 198 – 288) and s.d. 21 (95% CI = 1 – 66) days. These results suggest that adult survival is the most likely proximate cause of the decline. They also demonstrate a novel technique for attaining age-specific mortality rates from telemetry data.Responses of male sperm whales (Physeter macrocephalus) to killer whale sounds : implications for anti-predator strategieshttp://hdl.handle.net/10023/4410
Interactions between individuals of different cetacean species are often observed in the wild. Killer whales (Orcinus orca) can be potential predators of many other cetaceans, and the interception of their vocalizations by unintended cetacean receivers may trigger anti-predator behavior that could mediate predator-prey interactions. We explored the anti-predator behaviour of five typically-solitary male sperm whales (Physeter macrocephalus) in the Norwegian Sea by playing sounds of mammal-feeding killer whales and monitoring behavioural responses using multi-sensor tags. Our results suggest that, rather than taking advantage of their large aerobic capacities to dive away from the perceived predator, sperm whales responded to killer whale playbacks by interrupting their foraging or resting dives and returning to the surface, changing their vocal production, and initiating a surprising degree of social behaviour in these mostly solitary animals. Thus, the interception of predator vocalizations by male sperm whales disrupted functional behaviours and mediated previously unrecognized anti-predator responses.
Tue, 02 Apr 2013 00:00:00 GMThttp://hdl.handle.net/10023/44102013-04-02T00:00:00ZCure, CharlotteAntunes, Ricardo NunoAlves, Ana Catarina De CarvalhoVisser, FleurKvadsheim, Petter H.Miller, PatrickInteractions between individuals of different cetacean species are often observed in the wild. Killer whales (Orcinus orca) can be potential predators of many other cetaceans, and the interception of their vocalizations by unintended cetacean receivers may trigger anti-predator behavior that could mediate predator-prey interactions. We explored the anti-predator behaviour of five typically-solitary male sperm whales (Physeter macrocephalus) in the Norwegian Sea by playing sounds of mammal-feeding killer whales and monitoring behavioural responses using multi-sensor tags. Our results suggest that, rather than taking advantage of their large aerobic capacities to dive away from the perceived predator, sperm whales responded to killer whale playbacks by interrupting their foraging or resting dives and returning to the surface, changing their vocal production, and initiating a surprising degree of social behaviour in these mostly solitary animals. Thus, the interception of predator vocalizations by male sperm whales disrupted functional behaviours and mediated previously unrecognized anti-predator responses.Control of mode and intermediate water mass properties in Drake Passage by the Amundsen Sea lowhttp://hdl.handle.net/10023/4370
The evolution of the physical properties of Subantarctic Mode Water (SAMW) and Antarctic Intermediate Water (AAIW) in the Drake Passage region are examined on time scales down to intraseasonal, within the 1969 - 2009 period. Both SAMW and AAIW experience substantial interannual to interdecadal variability, significantly linked to the action of the Amundsen Sea Low (ASL) in their formation areas. Observations suggest that the interdecadal freshening tendency evident in SAMW over the past three decades has recently abated, whilst AAIW has warmed significantly since the early 2000s. The two water masses have also experienced a substantial lightening since the start of the record. Examination of the mechanisms underpinning water mass property variability shows that SAMW characteristics are controlled predominantly by a combination of air-sea turbulent heat fluxes, cross-frontal Ekman transport of Antarctic surface waters and the evaporation-precipitation balance, whilst AAIW properties reflect air-sea turbulent heat fluxes and sea ice formation in the Bellingshausen Sea. The recent interdecadal evolution of the ASL is consistent with both the dominance of the processes described here and the response of SAMW and AAIW on that time scale.
Mon, 01 Jul 2013 00:00:00 GMThttp://hdl.handle.net/10023/43702013-07-01T00:00:00ZClose, SallyNaveira Garabato, AlbertoMcDonagh, ElaineKing, BrianBiuw, MartinBoehme, LarsThe evolution of the physical properties of Subantarctic Mode Water (SAMW) and Antarctic Intermediate Water (AAIW) in the Drake Passage region are examined on time scales down to intraseasonal, within the 1969 - 2009 period. Both SAMW and AAIW experience substantial interannual to interdecadal variability, significantly linked to the action of the Amundsen Sea Low (ASL) in their formation areas. Observations suggest that the interdecadal freshening tendency evident in SAMW over the past three decades has recently abated, whilst AAIW has warmed significantly since the early 2000s. The two water masses have also experienced a substantial lightening since the start of the record. Examination of the mechanisms underpinning water mass property variability shows that SAMW characteristics are controlled predominantly by a combination of air-sea turbulent heat fluxes, cross-frontal Ekman transport of Antarctic surface waters and the evaporation-precipitation balance, whilst AAIW properties reflect air-sea turbulent heat fluxes and sea ice formation in the Bellingshausen Sea. The recent interdecadal evolution of the ASL is consistent with both the dominance of the processes described here and the response of SAMW and AAIW on that time scale.Estimates of the Southern Ocean general circulation improved by animal-borne instrumentshttp://hdl.handle.net/10023/4312
Over the last decade, several hundred seals have been equipped with conductivity-temperature-depth (CTD) sensors in the Southern Ocean for both biological and physical oceanographic studies. A calibrated collection of seal-derived hydrographic data is now available, consisting of more than 165,000 profiles. The value of these hydrographic data within the existing Southern Ocean observing system is demonstrated herein by conducting two state estimation experiments, differing only in the use or not of seal data to constrain the system. Including seal-derived data substantially modifies the estimated surface mixed-layer properties and circulation patterns within and south of the Antarctic Circumpolar Current. Agreement with independent satellite observations of sea-ice concentration is improved, especially along the East Antarctic shelf. Instrumented animals efficiently reduce a critical observational gap, and their contribution to monitoring polar climate variability will continue to grow as data accuracy and spatial coverage increase.
Sun, 01 Dec 2013 00:00:00 GMThttp://hdl.handle.net/10023/43122013-12-01T00:00:00ZRoquet, FWunsch, CForget, GHeimbach, PGuinet, CReverdin, GCharrassin, J-BBailleul, FCosta, D PHuckstadt, L AGoetz, K TKovacs, K MLydersen, CBiuw, MNøst, O ABornemann, HPloetz, JBester, M NMcIntyre, TMuelbert, M CHindell, MMcMahon, C RWilliams, GHarcourt, RField, IChafik, LNicholls, K WBoehme, LarsFedak, MikeOver the last decade, several hundred seals have been equipped with conductivity-temperature-depth (CTD) sensors in the Southern Ocean for both biological and physical oceanographic studies. A calibrated collection of seal-derived hydrographic data is now available, consisting of more than 165,000 profiles. The value of these hydrographic data within the existing Southern Ocean observing system is demonstrated herein by conducting two state estimation experiments, differing only in the use or not of seal data to constrain the system. Including seal-derived data substantially modifies the estimated surface mixed-layer properties and circulation patterns within and south of the Antarctic Circumpolar Current. Agreement with independent satellite observations of sea-ice concentration is improved, especially along the East Antarctic shelf. Instrumented animals efficiently reduce a critical observational gap, and their contribution to monitoring polar climate variability will continue to grow as data accuracy and spatial coverage increase.Investigating annual diving behaviour by Hooded seals (Cystophora cristata) within the Northwest Atlantic Oceanhttp://hdl.handle.net/10023/4228
With the exception of relatively brief periods when they reproduce and moult, hooded seals, Cystophora cristata, spend most of the year in the open ocean where they undergo feeding migrations to either recover or prepare for the next fasting period. Valuable insights into habitat use and diving behaviour during these periods have been obtained by attaching Satellite Relay Data Loggers (SRDLs) to 51 Northwest (NW) Atlantic hooded seals (33 females and 18 males) during ice-bound fasting periods (2004−2008). Using General Additive Models (GAMs) we describe habitat use in terms of First Passage Time (FPT) and analyse how bathymetry, seasonality and FPT influence the hooded seals’ diving behaviour described by maximum dive depth, dive duration and surface duration. Adult NW Atlantic hooded seals exhibit a change in diving activity in areas where they spend >20 h by increasing maximum dive depth, dive duration and surface duration, indicating a restricted search behaviour. We found that male and female hooded seals are spatially segregated and that diving behaviour varies between sexes in relation to habitat properties and seasonality. Migration periods are described by increased dive duration for both sexes with a peak in May, October and January. Males demonstrated an increase in dive depth and dive duration towards May (post-breeding/pre-moult) and August–October (post-moult/pre-breeding) but did not show any pronounced increase in surface duration. Females dived deepest and had the highest surface duration between December and January (post-moult/pre-breeding). Our results suggest that the smaller females may have a greater need to recover from dives than that of the larger males. Horizontal segregation could have evolved as a result of a resource partitioning strategy to avoid sexual competition or that the energy requirements of males and females are different due to different energy expenditure during fasting periods.
This work was funded through the Atlantic Seal Research Programme, International Governance Programme (DFO), the Greenland Institute of Natural Resources, and a CFI grant to YFW. The authors also acknowledge the support of the Marine Alliance for Science and Technology for Scotland (MASTS) pooling initiative in the completion of this study. MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Mon, 25 Nov 2013 00:00:00 GMThttp://hdl.handle.net/10023/42282013-11-25T00:00:00ZAndersen, Julie MarieSkern-Mauritzen, MetteBoehme, LarsWiersma, Yolanda F.Rosvig-Asvid, AqqaluHammill, MikeStenson, GarryWith the exception of relatively brief periods when they reproduce and moult, hooded seals, Cystophora cristata, spend most of the year in the open ocean where they undergo feeding migrations to either recover or prepare for the next fasting period. Valuable insights into habitat use and diving behaviour during these periods have been obtained by attaching Satellite Relay Data Loggers (SRDLs) to 51 Northwest (NW) Atlantic hooded seals (33 females and 18 males) during ice-bound fasting periods (2004−2008). Using General Additive Models (GAMs) we describe habitat use in terms of First Passage Time (FPT) and analyse how bathymetry, seasonality and FPT influence the hooded seals’ diving behaviour described by maximum dive depth, dive duration and surface duration. Adult NW Atlantic hooded seals exhibit a change in diving activity in areas where they spend >20 h by increasing maximum dive depth, dive duration and surface duration, indicating a restricted search behaviour. We found that male and female hooded seals are spatially segregated and that diving behaviour varies between sexes in relation to habitat properties and seasonality. Migration periods are described by increased dive duration for both sexes with a peak in May, October and January. Males demonstrated an increase in dive depth and dive duration towards May (post-breeding/pre-moult) and August–October (post-moult/pre-breeding) but did not show any pronounced increase in surface duration. Females dived deepest and had the highest surface duration between December and January (post-moult/pre-breeding). Our results suggest that the smaller females may have a greater need to recover from dives than that of the larger males. Horizontal segregation could have evolved as a result of a resource partitioning strategy to avoid sexual competition or that the energy requirements of males and females are different due to different energy expenditure during fasting periods.Following a foraging fish-finder : Diel habitat use of Blainville's beaked whales revealed by echolocationhttp://hdl.handle.net/10023/4156
Simultaneous high resolution sampling of predator behavior and habitat characteristics is often difficult to achieve despite its importance in understanding the foraging decisions and habitat use of predators. Here we tap into the biosonar system of Blainville's beaked whales, Mesoplodon densirostris, using sound and orientation recording tags to uncover prey-finding cues available to echolocating predators in the deep-sea. Echolocation sounds indicate where whales search and encounter prey, as well as the altitude of whales above the sea-floor and the density of organisms around them, providing a link between foraging activity and the bio-physical environment. Tagged whales (n = 9) hunted exclusively at depth, investing most of their search time either in the lower part of the deep scattering layer (DSL) or near the sea-floor with little diel change. At least 43% (420/974) of recorded prey-capture attempts were performed within the benthic boundary layer despite a wide range of dive depths, and many dives included both meso-and bentho-pelagic foraging. Blainville's beaked whales only initiate searching when already deep in the descent and encounter prey suitable for capture within 2 min of the start of echolocation, suggesting that these whales are accessing prey in reliable vertical strata. Moreover, these prey resources are sufficiently dense to feed the animals in what is effectively four hours of hunting per day enabling a strategy in which long dives to exploit numerous deep-prey with low nutritional value require protracted recovery periods (average 1.5 h) between dives. This apparent searching efficiency maybe aided by inhabiting steep undersea slopes with access to both the DSL and the sea-floor over small spatial scales. Aggregations of prey in these biotopes are located using biosonar-derived landmarks and represent stable and abundant resources for Blainville's beaked whales in the otherwise food-limited deep-ocean.
The work was funded by the Office of Naval Research and the National Ocean Partnership Program (US), by a consortium consisting of the Canary Islands Government, the Spanish Ministry of Environment and the Spanish Ministry of Defense, and by the European environmental funding LIFE-INDEMA RES program for the inventory and designation of the Natura 2000 network in marine areas of the Spanish territory, headed by Fundacion Biodiversidad, with additional support from the Cabildo Insular of El Hierro. PA is currently supported by the National Research Project: Cetacean, Oceanography and Bio diversity from La Palma and El Hierro (CGL2009-13112) of the Spanish Ministry of Science and NAS by a Marie Curie fellowship from the 7th European Frame Program. MJ was supported by grants from the Strategic Environmental Research Development Program and from the National Ocean Partnership Program. PTM was supported by frame grants from the National Danish Science Foundation. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Wed, 07 Dec 2011 00:00:00 GMThttp://hdl.handle.net/10023/41562011-12-07T00:00:00ZArranz, PatriciaAguilar de Soto, NatachaMadsen, Peter T.Brito, AlbertoBordes, FernandoJohnson, Mark P.Simultaneous high resolution sampling of predator behavior and habitat characteristics is often difficult to achieve despite its importance in understanding the foraging decisions and habitat use of predators. Here we tap into the biosonar system of Blainville's beaked whales, Mesoplodon densirostris, using sound and orientation recording tags to uncover prey-finding cues available to echolocating predators in the deep-sea. Echolocation sounds indicate where whales search and encounter prey, as well as the altitude of whales above the sea-floor and the density of organisms around them, providing a link between foraging activity and the bio-physical environment. Tagged whales (n = 9) hunted exclusively at depth, investing most of their search time either in the lower part of the deep scattering layer (DSL) or near the sea-floor with little diel change. At least 43% (420/974) of recorded prey-capture attempts were performed within the benthic boundary layer despite a wide range of dive depths, and many dives included both meso-and bentho-pelagic foraging. Blainville's beaked whales only initiate searching when already deep in the descent and encounter prey suitable for capture within 2 min of the start of echolocation, suggesting that these whales are accessing prey in reliable vertical strata. Moreover, these prey resources are sufficiently dense to feed the animals in what is effectively four hours of hunting per day enabling a strategy in which long dives to exploit numerous deep-prey with low nutritional value require protracted recovery periods (average 1.5 h) between dives. This apparent searching efficiency maybe aided by inhabiting steep undersea slopes with access to both the DSL and the sea-floor over small spatial scales. Aggregations of prey in these biotopes are located using biosonar-derived landmarks and represent stable and abundant resources for Blainville's beaked whales in the otherwise food-limited deep-ocean.The encoding of individual identity in dolphin signature whistles : how much information is needed?http://hdl.handle.net/10023/4142
Bottlenose dolphins (Tursiops truncatus) produce many vocalisations, including whistles that are unique to the individual producing them. Such “signature whistles” play a role in individual recognition and maintaining group integrity. Previous work has shown that humans can successfully group the spectrographic representations of signature whistles according to the individual dolphins that produced them. However, attempts at using mathematical algorithms to perform a similar task have been less successful. A greater understanding of the encoding of identity information in signature whistles is important for assessing similarity of whistles and thus social influences on the development of these learned calls. We re-examined 400 signature whistles from 20 individual dolphins used in a previous study, and tested the performance of new mathematical algorithms. We compared the measure used in the original study (correlation matrix of evenly sampled frequency measurements) to one used in several previous studies (similarity matrix of time-warped whistles), and to a new algorithm based on the Parsons code, used in music retrieval databases. The Parsons code records the direction of frequency change at each time step, and is effective at capturing human perception of music. We analysed similarity matrices from each of these three techniques, as well as a random control, by unsupervised clustering using three separate techniques: k-means clustering, hierarchical clustering, and an adaptive resonance theory neural network. For each of the three clustering techniques, a seven-level Parsons algorithm provided better clustering than the correlation and dynamic time warping algorithms, and was closer to the near-perfect visual categorisations of human judges. Thus, the Parsons code captures much of the individual identity information present in signature whistles, and may prove useful in studies requiring quantification of whistle similarity.
Wed, 23 Oct 2013 00:00:00 GMThttp://hdl.handle.net/10023/41422013-10-23T00:00:00ZKershenbaum, ArikSayigh, LaelaJanik, Vincent M.Bottlenose dolphins (Tursiops truncatus) produce many vocalisations, including whistles that are unique to the individual producing them. Such “signature whistles” play a role in individual recognition and maintaining group integrity. Previous work has shown that humans can successfully group the spectrographic representations of signature whistles according to the individual dolphins that produced them. However, attempts at using mathematical algorithms to perform a similar task have been less successful. A greater understanding of the encoding of identity information in signature whistles is important for assessing similarity of whistles and thus social influences on the development of these learned calls. We re-examined 400 signature whistles from 20 individual dolphins used in a previous study, and tested the performance of new mathematical algorithms. We compared the measure used in the original study (correlation matrix of evenly sampled frequency measurements) to one used in several previous studies (similarity matrix of time-warped whistles), and to a new algorithm based on the Parsons code, used in music retrieval databases. The Parsons code records the direction of frequency change at each time step, and is effective at capturing human perception of music. We analysed similarity matrices from each of these three techniques, as well as a random control, by unsupervised clustering using three separate techniques: k-means clustering, hierarchical clustering, and an adaptive resonance theory neural network. For each of the three clustering techniques, a seven-level Parsons algorithm provided better clustering than the correlation and dynamic time warping algorithms, and was closer to the near-perfect visual categorisations of human judges. Thus, the Parsons code captures much of the individual identity information present in signature whistles, and may prove useful in studies requiring quantification of whistle similarity.Clicking in Shallow Rivers : Short-Range Echolocation of Irrawaddy and Ganges River Dolphins in a Shallow, Acoustically Complex Habitathttp://hdl.handle.net/10023/4141
Toothed whales (Cetacea, odontoceti) use biosonar to navigate their environment and to find and catch prey. All studied toothed whale species have evolved highly directional, high-amplitude ultrasonic clicks suited for long-range echolocation of prey in open water. Little is known about the biosonar signals of toothed whale species inhabiting freshwater habitats such as endangered river dolphins. To address the evolutionary pressures shaping the echolocation signal parameters of non-marine toothed whales, we investigated the biosonar source parameters of Ganges river dolphins (Platanista gangetica gangetica) and Irrawaddy dolphins (Orcaella brevirostris) within the river systems of the Sundarban mangrove forest. Both Ganges and Irrawaddy dolphins produced echolocation clicks with a high repetition rate and low source level compared to marine species. Irrawaddy dolphins, inhabiting coastal and riverine habitats, produced a mean source level of 195 dB (max 203 dB) re 1 µPapp whereas Ganges river dolphins, living exclusively upriver, produced a mean source level of 184 dB (max 191) re 1 µPapp. These source levels are 1–2 orders of magnitude lower than those of similar sized marine delphinids and may reflect an adaptation to a shallow, acoustically complex freshwater habitat with high reverberation and acoustic clutter. The centroid frequency of Ganges river dolphin clicks are an octave lower than predicted from scaling, but with an estimated beamwidth comparable to that of porpoises. The unique bony maxillary crests found in the Platanista forehead may help achieve a higher directionality than expected using clicks nearly an octave lower than similar sized odontocetes.
Wed, 03 Apr 2013 00:00:00 GMThttp://hdl.handle.net/10023/41412013-04-03T00:00:00ZJensen, FrantsRocco, AliceMansur, RubaiyatSmith, BrianJanik, Vincent M.Madsen, PeterToothed whales (Cetacea, odontoceti) use biosonar to navigate their environment and to find and catch prey. All studied toothed whale species have evolved highly directional, high-amplitude ultrasonic clicks suited for long-range echolocation of prey in open water. Little is known about the biosonar signals of toothed whale species inhabiting freshwater habitats such as endangered river dolphins. To address the evolutionary pressures shaping the echolocation signal parameters of non-marine toothed whales, we investigated the biosonar source parameters of Ganges river dolphins (Platanista gangetica gangetica) and Irrawaddy dolphins (Orcaella brevirostris) within the river systems of the Sundarban mangrove forest. Both Ganges and Irrawaddy dolphins produced echolocation clicks with a high repetition rate and low source level compared to marine species. Irrawaddy dolphins, inhabiting coastal and riverine habitats, produced a mean source level of 195 dB (max 203 dB) re 1 µPapp whereas Ganges river dolphins, living exclusively upriver, produced a mean source level of 184 dB (max 191) re 1 µPapp. These source levels are 1–2 orders of magnitude lower than those of similar sized marine delphinids and may reflect an adaptation to a shallow, acoustically complex freshwater habitat with high reverberation and acoustic clutter. The centroid frequency of Ganges river dolphin clicks are an octave lower than predicted from scaling, but with an estimated beamwidth comparable to that of porpoises. The unique bony maxillary crests found in the Platanista forehead may help achieve a higher directionality than expected using clicks nearly an octave lower than similar sized odontocetes.Pilot whales attracted to killer whales sounds : acoustically-mediated interspecific interactions in cetaceanshttp://hdl.handle.net/10023/4134
In cetaceans’ communities, interactions between individuals of different species are often observed in the wild. Yet, due to methodological and technical challenges very little is known about the mediation of these interactions and their effect on cetaceans’ behavior. Killer whales (Orcinus orca) are a highly vocal species and can be both food competitors and potential predators of many other cetaceans. Thus, the interception of their vocalizations by unintended cetacean receivers may be particularly important in mediating interspecific interactions. To address this hypothesis, we conducted playbacks of killer whale vocalizations recorded during herring-feeding activity to free-ranging long-finned pilot whales (Globicephala melas). Using a multi-sensor tag, we were able to track the whales and to monitor changes of their movements and social behavior in response to the playbacks. We demonstrated that the playback of killer whale sounds to pilot whales induced a clear increase in group size and a strong attraction of the animals towards the sound source. These findings provide the first experimental evidence that the interception of heterospecific vocalizations can mediate interactions between different cetacean species in previously unrecognized ways.
This study was mainly funded by three naval organisations: the US Office of Naval Research, the Norwegian Ministry of Defense and the Netherlands Ministry of Defense. In addition, WWF-Norway, TOTAL Foundation and the Foundation Bleustein-Blanchet also contributed financially. Authors are employed by government (Norwegian Defense Research Establishment), independent no-profit (Netherlands Organization for Applied Scientific Research and Kelp Marine Research), or academic (University of St. Andrews) research organisations. No authors are employed by naval organisations. The funders had no role in study design, data analysis, or preparation of the manuscript.
Wed, 26 Dec 2012 00:00:00 GMThttp://hdl.handle.net/10023/41342012-12-26T00:00:00ZCuré, CharlotteAntunes, Ricardo NunoSamarra, Filipa Isabel PereiraAlves, Ana Catarina De CarvalhoVisser, FleurKvadsheim, Petter H.Miller, PatrickIn cetaceans’ communities, interactions between individuals of different species are often observed in the wild. Yet, due to methodological and technical challenges very little is known about the mediation of these interactions and their effect on cetaceans’ behavior. Killer whales (Orcinus orca) are a highly vocal species and can be both food competitors and potential predators of many other cetaceans. Thus, the interception of their vocalizations by unintended cetacean receivers may be particularly important in mediating interspecific interactions. To address this hypothesis, we conducted playbacks of killer whale vocalizations recorded during herring-feeding activity to free-ranging long-finned pilot whales (Globicephala melas). Using a multi-sensor tag, we were able to track the whales and to monitor changes of their movements and social behavior in response to the playbacks. We demonstrated that the playback of killer whale sounds to pilot whales induced a clear increase in group size and a strong attraction of the animals towards the sound source. These findings provide the first experimental evidence that the interception of heterospecific vocalizations can mediate interactions between different cetacean species in previously unrecognized ways.Anthropogenic noise causes body malformations and delays development in marine larvaehttp://hdl.handle.net/10023/4083
Understanding the impact of noise on marine fauna at the population level requires knowledge about the vulnerability of different life-stages. Here we provide the first evidence that noise exposure during larval development produces body malformations in marine invertebrates. Scallop larvae exposed to playbacks of seismic pulses showed significant developmental delays and 46% developed body abnormalities. Similar effects were observed in all independent samples exposed to noise while no malformations were found in the control groups (4881 larvae examined). Malformations appeared in the D-veliger larval phase, perhaps due to the cumulative exposure attained by this stage or to a greater vulnerability of D-veliger to sound-mediated physiological or mechanical stress. Such strong impacts suggest that abnormalities and growth delays may also result from lower sound levels or discrete exposures during the D-stage, increasing the potential for routinely-occurring anthropogenic noise sources to affect recruitment of wild scallop larvae in natural stocks.
Thu, 03 Oct 2013 00:00:00 GMThttp://hdl.handle.net/10023/40832013-10-03T00:00:00ZAguilar de Soto, NatachaDelorme, NataliAtkins, JohnHoward, SunkitaWilliams, JamesJohnson, MarkUnderstanding the impact of noise on marine fauna at the population level requires knowledge about the vulnerability of different life-stages. Here we provide the first evidence that noise exposure during larval development produces body malformations in marine invertebrates. Scallop larvae exposed to playbacks of seismic pulses showed significant developmental delays and 46% developed body abnormalities. Similar effects were observed in all independent samples exposed to noise while no malformations were found in the control groups (4881 larvae examined). Malformations appeared in the D-veliger larval phase, perhaps due to the cumulative exposure attained by this stage or to a greater vulnerability of D-veliger to sound-mediated physiological or mechanical stress. Such strong impacts suggest that abnormalities and growth delays may also result from lower sound levels or discrete exposures during the D-stage, increasing the potential for routinely-occurring anthropogenic noise sources to affect recruitment of wild scallop larvae in natural stocks.Prioritizing global marine mammal habitats using density maps in place of range mapshttp://hdl.handle.net/10023/4068
Despite lessons from terrestrial systems, conservation efforts in marine systems continue to focus on identifying priority sites for protection based on high species richness inferred from range maps. Range maps oversimplify spatial variability in animal distributions by assuming uniform distribution within range and de facto giving equal weight to critical and marginal habitats. We used Marxan ver. 2.43 to compare species richness-based systematic reserve network solutions using information about marine mammal range and relative abundance. At a global scale, reserve network solutions were strongly sensitive to model inputs and assumptions. Solutions based on different input data overlapped by a third at most, with agreement as low as 10% in some cases. At a regional scale, species richness was inversely related to density, such that species richness hotspots excluded highest-density areas for all species. Based on these findings, we caution that species-richness estimates derived from range maps and used as input in conservation planning exercises may inadvertently lead to protection of largely marginal habitat.
RW was supported by a Marie Curie International Incoming Fellowship within the 7th European Community Framework Programme FP7-PEOPLE-2009-IIF
Sat, 01 Mar 2014 00:00:00 GMThttp://hdl.handle.net/10023/40682014-03-01T00:00:00ZWilliams, RobertGrand, JoannaHooker, Sascha KateBuckland, Stephen TerrenceReeves, Randall R.Rojas-Bracho, LorenzoSandilands, DougKaschner, KristinDespite lessons from terrestrial systems, conservation efforts in marine systems continue to focus on identifying priority sites for protection based on high species richness inferred from range maps. Range maps oversimplify spatial variability in animal distributions by assuming uniform distribution within range and de facto giving equal weight to critical and marginal habitats. We used Marxan ver. 2.43 to compare species richness-based systematic reserve network solutions using information about marine mammal range and relative abundance. At a global scale, reserve network solutions were strongly sensitive to model inputs and assumptions. Solutions based on different input data overlapped by a third at most, with agreement as low as 10% in some cases. At a regional scale, species richness was inversely related to density, such that species richness hotspots excluded highest-density areas for all species. Based on these findings, we caution that species-richness estimates derived from range maps and used as input in conservation planning exercises may inadvertently lead to protection of largely marginal habitat.Using energetic models to investigate the survival and reproduction of beaked whales (family Ziphiidae)http://hdl.handle.net/10023/4053
Mass stranding of several species of beaked whales (family Ziphiidae) associated with exposure to anthropogenic sounds has raised concern for the conservation of these species. However, little is known about the species’ life histories, prey or habitat requirements. Without this knowledge, it becomes difficult to assess the effects of anthropogenic sound, since there is no way to determine whether the disturbance is impacting the species’ physical or environmental requirements. Here we take a bioenergetics approach to address this gap in our knowledge, as the elusive, deep-diving nature of beaked whales has made it hard to study these effects directly. We develop a model for Ziphiidae linking feeding energetics to the species’ requirements for survival and reproduction, since these life history traits would be the most likely to be impacted by non-lethal disturbances. Our models suggest that beaked whale reproduction requires energy dense prey, and that poor resource availability would lead to an extension of the inter-calving interval. Further, given current information, it seems that some beaked whale species require relatively high quality habitat in order to meet their requirements for survival and reproduction. As a result, even a small non-lethal disturbance that results in displacement of whales from preferred habitats could potentially impact a population if a significant proportion of that population was affected. We explored the impact of varying ecological parameters and model assumptions on survival and reproduction, and find that calf and fetus survival appear more readily affected than the survival of adult females.
Wed, 17 Jul 2013 00:00:00 GMThttp://hdl.handle.net/10023/40532013-07-17T00:00:00ZNew, Leslie FrancesMoretti, DavidHooker, Sascha KateCosta, Daniel P.Simmons, Samantha E.Mass stranding of several species of beaked whales (family Ziphiidae) associated with exposure to anthropogenic sounds has raised concern for the conservation of these species. However, little is known about the species’ life histories, prey or habitat requirements. Without this knowledge, it becomes difficult to assess the effects of anthropogenic sound, since there is no way to determine whether the disturbance is impacting the species’ physical or environmental requirements. Here we take a bioenergetics approach to address this gap in our knowledge, as the elusive, deep-diving nature of beaked whales has made it hard to study these effects directly. We develop a model for Ziphiidae linking feeding energetics to the species’ requirements for survival and reproduction, since these life history traits would be the most likely to be impacted by non-lethal disturbances. Our models suggest that beaked whale reproduction requires energy dense prey, and that poor resource availability would lead to an extension of the inter-calving interval. Further, given current information, it seems that some beaked whale species require relatively high quality habitat in order to meet their requirements for survival and reproduction. As a result, even a small non-lethal disturbance that results in displacement of whales from preferred habitats could potentially impact a population if a significant proportion of that population was affected. We explored the impact of varying ecological parameters and model assumptions on survival and reproduction, and find that calf and fetus survival appear more readily affected than the survival of adult females.Foraging dives of sperm whales in the north-western Mediterranean Seahttp://hdl.handle.net/10023/4031
Oceanic odontocetes rely on echolocation to forage on pelagic or benthic prey, but their feeding ecology is difficult to study. We studied sperm whale foraging dives during summer in the north-western Mediterranean, using visual and passive acoustic observations. Clicking and creaking activities were recorded during dives of focal whales, at distances <3000 m using a towed hydrophone and DAT recorder. A total of 52 sperm whales were recorded over at least one full dive cycle. Data were obtained for 156 complete dives in total, including sequences of up to nine consecutive dives. Various dive and environmental variables were entered in multiple linear regression and principal components analysis, as well as estimated mass of whales. Creak rate was 0.80 creak/minute on average, with moderate variance. Bigger whales tended to dive longer at greater depths (as suggested by ascent durations), and emitted more creaks during a dive: 20.2 creaks/dive on average for individuals <24 tons, compared to 25.6 creaks/dive for animals >24 tons of estimated mass. For individual whales, creak rates did not vary significantly with size (range 0.78–0.80 creak/minute), but decreased with time of the day, and increased for shorter foraging phases. For different dives, higher creak rates were also observed earlier in the day, and linked to shorter foraging phases and surface durations. Although the exact significance of creak emissions (i.e. foraging attempt or prey capture) is not precisely determined, creak rates may be reliably used to quantify sperm whale foraging when single animal dives can be followed acoustically.
Sat, 01 Dec 2012 00:00:00 GMThttp://hdl.handle.net/10023/40312012-12-01T00:00:00ZGannier, AlexandrePetiau, EstelleDulau, ViolaineRendell, LukeOceanic odontocetes rely on echolocation to forage on pelagic or benthic prey, but their feeding ecology is difficult to study. We studied sperm whale foraging dives during summer in the north-western Mediterranean, using visual and passive acoustic observations. Clicking and creaking activities were recorded during dives of focal whales, at distances <3000 m using a towed hydrophone and DAT recorder. A total of 52 sperm whales were recorded over at least one full dive cycle. Data were obtained for 156 complete dives in total, including sequences of up to nine consecutive dives. Various dive and environmental variables were entered in multiple linear regression and principal components analysis, as well as estimated mass of whales. Creak rate was 0.80 creak/minute on average, with moderate variance. Bigger whales tended to dive longer at greater depths (as suggested by ascent durations), and emitted more creaks during a dive: 20.2 creaks/dive on average for individuals <24 tons, compared to 25.6 creaks/dive for animals >24 tons of estimated mass. For individual whales, creak rates did not vary significantly with size (range 0.78–0.80 creak/minute), but decreased with time of the day, and increased for shorter foraging phases. For different dives, higher creak rates were also observed earlier in the day, and linked to shorter foraging phases and surface durations. Although the exact significance of creak emissions (i.e. foraging attempt or prey capture) is not precisely determined, creak rates may be reliably used to quantify sperm whale foraging when single animal dives can be followed acoustically.Combining individual animal movement and ancillary biotelemetry data to investigate population-level activity budgetshttp://hdl.handle.net/10023/3993
Recent technological advances have permitted the collection of detailed animal location and ancillary biotelemetry data that facilitate inference about animal movement and associated behaviors. However, these rich sources of individual information, location, and biotelemetry data, are typically analyzed independently, with population-level inferences remaining largely post hoc. We describe a hierarchical modeling approach, which is able to integrate location and ancillary biotelemetry (e.g., physiological or accelerometer) data from many individuals. We can thus obtain robust estimates of (1) population-level movement parameters and (2) activity budgets for a set of behaviors among which animals transition as they respond to changes in their internal and external environment. Measurement error and missing data are easily accommodated using a state-space formulation of the proposed hierarchical model. Using Bayesian analysis methods, we demonstrate our modeling approach with location and dive activity data from 17 harbor seals (Phoca vitulina) in the United Kingdom. Based jointly on movement and diving activity, we identified three distinct movement behavior states: resting, foraging, and transit, and estimated population-level activity budgets to these three states. Because harbor seals are known to dive for both foraging and transit (but not usually for resting), we compared these results to a similar population level analysis utilizing only location data. We found that a large proportion of time steps were mischaracterized when behavior states were inferred from horizontal trajectory alone, with 33% of time steps exhibiting a majority of dive activity assigned to the resting state. Only 1% of these time steps were assigned to resting when inferred from both trajectory and dive activity data using our integrated modeling approach. There is mounting evidence of the potential perils of inferring animal behavior based on trajectory alone, but there fortunately now exist many flexible analytical techniques for extracting more out of the increasing wealth of information afforded by recent advances in biologging technology.
Mon, 01 Apr 2013 00:00:00 GMThttp://hdl.handle.net/10023/39932013-04-01T00:00:00ZMcClintock, Brett ThomasRussell, Deborah Jill FraserMatthiopoulos, JasonKing, RuthRecent technological advances have permitted the collection of detailed animal location and ancillary biotelemetry data that facilitate inference about animal movement and associated behaviors. However, these rich sources of individual information, location, and biotelemetry data, are typically analyzed independently, with population-level inferences remaining largely post hoc. We describe a hierarchical modeling approach, which is able to integrate location and ancillary biotelemetry (e.g., physiological or accelerometer) data from many individuals. We can thus obtain robust estimates of (1) population-level movement parameters and (2) activity budgets for a set of behaviors among which animals transition as they respond to changes in their internal and external environment. Measurement error and missing data are easily accommodated using a state-space formulation of the proposed hierarchical model. Using Bayesian analysis methods, we demonstrate our modeling approach with location and dive activity data from 17 harbor seals (Phoca vitulina) in the United Kingdom. Based jointly on movement and diving activity, we identified three distinct movement behavior states: resting, foraging, and transit, and estimated population-level activity budgets to these three states. Because harbor seals are known to dive for both foraging and transit (but not usually for resting), we compared these results to a similar population level analysis utilizing only location data. We found that a large proportion of time steps were mischaracterized when behavior states were inferred from horizontal trajectory alone, with 33% of time steps exhibiting a majority of dive activity assigned to the resting state. Only 1% of these time steps were assigned to resting when inferred from both trajectory and dive activity data using our integrated modeling approach. There is mounting evidence of the potential perils of inferring animal behavior based on trajectory alone, but there fortunately now exist many flexible analytical techniques for extracting more out of the increasing wealth of information afforded by recent advances in biologging technology.Intrinsic and extrinsic forcing in life histories : patterns of growth and stable isotopes in male Antarctic fur seal teethhttp://hdl.handle.net/10023/3969
Life-time records of the trophic sources of carbon, nitrogen and of growth rate can be generated from biogenic structures that show accretionary growth, including fish scales, whale baleen and the teeth of some animals. Records generated from individual teeth can also be combined to provide longer time series elucidating changes in environmental conditions encountered by a population. Both intrinsic (i.e. ontogenetic) and extrinsic (i.e. environmental) factors are important in modulating variation in growth and the apparent dietary sources of C and N. We used the canine teeth of a large marine predator, the male Antarctic fur seal Arctocephalus gazella from South Georgia, to investigate both intrinsic and extrinsic sources of variation. Substantial ontogenetic shifts occurred in both delta C-13 and delta N-15 values in individual teeth, indicating a change in the trophic sources of C and N as individual animals age. Over the 40 yr period from 1964 to 2005, and after statistical reduction of ontogenetic variation, we also detected long-term declines in delta C-13 and delta N-15 values, indicating that the population has become more dependent on energy from a lower trophic level. A concurrent decline in annular tooth growth may be a consequence of rapid population growth during this period. The time series of delta C-13 values was also inversely correlated with sea surface temperatures in the region, although isolating a causal relationship remains elusive. Our analyses suggest that both intrinsic and extrinsic sources of variation, and their interaction, must be considered from Such time series data; failure to do so could result in a biased interpretation.
Sat, 01 Aug 2009 00:00:00 GMThttp://hdl.handle.net/10023/39692009-08-01T00:00:00ZHanson, Nora NellWurster, Christopher MartinBird, Michael IanReid, KBoyd, Ian LamontLife-time records of the trophic sources of carbon, nitrogen and of growth rate can be generated from biogenic structures that show accretionary growth, including fish scales, whale baleen and the teeth of some animals. Records generated from individual teeth can also be combined to provide longer time series elucidating changes in environmental conditions encountered by a population. Both intrinsic (i.e. ontogenetic) and extrinsic (i.e. environmental) factors are important in modulating variation in growth and the apparent dietary sources of C and N. We used the canine teeth of a large marine predator, the male Antarctic fur seal Arctocephalus gazella from South Georgia, to investigate both intrinsic and extrinsic sources of variation. Substantial ontogenetic shifts occurred in both delta C-13 and delta N-15 values in individual teeth, indicating a change in the trophic sources of C and N as individual animals age. Over the 40 yr period from 1964 to 2005, and after statistical reduction of ontogenetic variation, we also detected long-term declines in delta C-13 and delta N-15 values, indicating that the population has become more dependent on energy from a lower trophic level. A concurrent decline in annular tooth growth may be a consequence of rapid population growth during this period. The time series of delta C-13 values was also inversely correlated with sea surface temperatures in the region, although isolating a causal relationship remains elusive. Our analyses suggest that both intrinsic and extrinsic sources of variation, and their interaction, must be considered from Such time series data; failure to do so could result in a biased interpretation.Wintertime water mass modification near an Antarctic Ice Shelf fronthttp://hdl.handle.net/10023/3903
Under ice measurements by seals carrying a miniaturized conductivity–temperature–depth (CTD) instrument fill an important gap in existing observations. Here we present data from an instrumented Weddell seal that spent 8 consecutive months (February–September) for aging in close proximity to Filchner Ice Shelf, thus providing detailed information about the evolution of mixed layer hydrography during the austral autumn and winter. The resultant time series of hydrography shows strong seasonal water mass modification, dominated by an upper–ocean (0–300 m) salinity increase of 0.31, corresponding to 3.1 m sea ice growth, and the development of a 500 m thick winter mixed layer. Observations furthermore highlight a gradual salinity increase in a slow (3–5 cms−1 ) southward flow on the continental shelf, to wards the site, and suggest that the inferred ice production is better considered as a regional average rather than being purely local. No clear seasonality is observed in the properties of the underlying Ice Shelf Water.
Fri, 01 Feb 2013 00:00:00 GMThttp://hdl.handle.net/10023/39032013-02-01T00:00:00ZArthun, MariusNicholls, KeithBoehme, LarsUnder ice measurements by seals carrying a miniaturized conductivity–temperature–depth (CTD) instrument fill an important gap in existing observations. Here we present data from an instrumented Weddell seal that spent 8 consecutive months (February–September) for aging in close proximity to Filchner Ice Shelf, thus providing detailed information about the evolution of mixed layer hydrography during the austral autumn and winter. The resultant time series of hydrography shows strong seasonal water mass modification, dominated by an upper–ocean (0–300 m) salinity increase of 0.31, corresponding to 3.1 m sea ice growth, and the development of a 500 m thick winter mixed layer. Observations furthermore highlight a gradual salinity increase in a slow (3–5 cms−1 ) southward flow on the continental shelf, to wards the site, and suggest that the inferred ice production is better considered as a regional average rather than being purely local. No clear seasonality is observed in the properties of the underlying Ice Shelf Water.Cetacean abundance and distribution in European Atlantic shelf waters to inform conservation and managementhttp://hdl.handle.net/10023/3859
The European Union (EU) Habitats Directive requires Member States to monitor and maintain at favourable conservation status those species identified to be in need of protection, including all cetaceans. In July 2005 we surveyed the entire EU Atlantic continental shelf to generate robust estimates of abundance for harbour porpoise and other cetacean species. The survey used line transect sampling methods and purpose built data collection equipment designed to minimise bias in estimates of abundance. Shipboard transects covered 19,725 km in sea conditions ⩽Beaufort 4 in an area of 1,005,743 km2. Aerial transects covered 15,802 km in good/moderate conditions (⩽Beaufort 3) in an area of 364,371 km2. Thirteen cetacean species were recorded; abundance was estimated for harbour porpoise (375,358; CV = 0.197), bottlenose dolphin (16,485; CV = 0.422), white-beaked dolphin (16,536; CV = 0.303), short-beaked common dolphin (56,221; CV = 0.234) and minke whale (18,958; CV = 0.347). Abundance in 2005 was similar to that estimated in July 1994 for harbour porpoise, white-beaked dolphin and minke whale in a comparable area. However, model-based density surfaces showed a marked difference in harbour porpoise distribution between 1994 and 2005. Our results allow EU Member States to discharge their responsibilities under the Habitats Directive and inform other international organisations concerning the assessment of conservation status of cetaceans and the impact of bycatch at a large spatial scale. The lack of evidence for a change in harbour porpoise abundance in EU waters as a whole does not exclude the possibility of an impact of bycatch in some areas. Monitoring bycatch and estimation of abundance continue to be essential.
This article was made open access through BIS OA funding.
Thu, 01 Aug 2013 00:00:00 GMThttp://hdl.handle.net/10023/38592013-08-01T00:00:00ZHammond, Philip StevenMacleod, KellyBerggren, PerBorchers, David LouisBurt, M LouiseCañadas, AnaDesportes, GenevieveDonovan, Greg PGilles, AnitaGillespie, Douglas MichaelGordon, Jonathan Charles DavidHiby, LexKuklik, IwonaLeaper, RussellLehnert, KristinaLeopold, MardikLovell, PhilipØien, NilsPaxton, Charles G. M.Ridoux, VincentRogan, EmerSamarra, Filipa Isabel PereiraScheidat, MeikeSequeira, MarinaSiebert, UrsulaSkov, HenrikSwift, Rene JamesTasker, MarkTeilmann, JonasVan Canneyt, OlivierVázquez, José AntonioThe European Union (EU) Habitats Directive requires Member States to monitor and maintain at favourable conservation status those species identified to be in need of protection, including all cetaceans. In July 2005 we surveyed the entire EU Atlantic continental shelf to generate robust estimates of abundance for harbour porpoise and other cetacean species. The survey used line transect sampling methods and purpose built data collection equipment designed to minimise bias in estimates of abundance. Shipboard transects covered 19,725 km in sea conditions ⩽Beaufort 4 in an area of 1,005,743 km2. Aerial transects covered 15,802 km in good/moderate conditions (⩽Beaufort 3) in an area of 364,371 km2. Thirteen cetacean species were recorded; abundance was estimated for harbour porpoise (375,358; CV = 0.197), bottlenose dolphin (16,485; CV = 0.422), white-beaked dolphin (16,536; CV = 0.303), short-beaked common dolphin (56,221; CV = 0.234) and minke whale (18,958; CV = 0.347). Abundance in 2005 was similar to that estimated in July 1994 for harbour porpoise, white-beaked dolphin and minke whale in a comparable area. However, model-based density surfaces showed a marked difference in harbour porpoise distribution between 1994 and 2005. Our results allow EU Member States to discharge their responsibilities under the Habitats Directive and inform other international organisations concerning the assessment of conservation status of cetaceans and the impact of bycatch at a large spatial scale. The lack of evidence for a change in harbour porpoise abundance in EU waters as a whole does not exclude the possibility of an impact of bycatch in some areas. Monitoring bycatch and estimation of abundance continue to be essential.Evidence for density-dependent changes in body condition and pregnancy rate of North Atlantic fin whales over four decades of varying environmental conditionshttp://hdl.handle.net/10023/3854
A central theme in ecology is the search for pattern in the response of a species to changing environmental conditions. Natural resource management and endangered species conservation require an understanding of density-dependent and density-independent factors that regulate populations. Marine mammal populations are expected to express density dependence in the same way as terrestrial mammals, but logistical difficulties in data acquisition for many large whale species have hindered attempts to identify population-regulation mechanisms. We explored relationships between body condition (inferred from patterns in blubber thickness) and per capita prey abundance, and between pregnancy rate and body condition in North Atlantic fin whales as environmental conditions and population size varied between 1967 and 2010. Blubber thickness in both males and females declined at low per capita prey availability, and in breeding-age females, pregnancy rate declined at low blubber thickness, demonstrating a density-dependent response of pregnancy to prey limitation mediated through body condition. To the best of our knowledge, this is the first time a quantitative relationship among per capita prey abundance, body condition, and pregnancy rate has been documented for whales. As long-lived predators, marine mammals can act as indicators of the state of marine ecosystems. Improving our understanding of the relationships that link prey, body condition, and population parameters such as pregnancy rate and survival will become increasingly useful as these systems are affected by natural and anthropogenic change. Quantifying linkages among prey, fitness and vital rates will improve our ability to predict population consequences of subtle, sublethal impacts of ocean noise and other anthropogenic stressors.
Fri, 01 Mar 2013 00:00:00 GMThttp://hdl.handle.net/10023/38542013-03-01T00:00:00ZWilliams, RobertVikingsson, Gisli A.Gislason, AstthorLockyer, ChristinaNew, LeslieThomas, LenHammond, Philip StevenA central theme in ecology is the search for pattern in the response of a species to changing environmental conditions. Natural resource management and endangered species conservation require an understanding of density-dependent and density-independent factors that regulate populations. Marine mammal populations are expected to express density dependence in the same way as terrestrial mammals, but logistical difficulties in data acquisition for many large whale species have hindered attempts to identify population-regulation mechanisms. We explored relationships between body condition (inferred from patterns in blubber thickness) and per capita prey abundance, and between pregnancy rate and body condition in North Atlantic fin whales as environmental conditions and population size varied between 1967 and 2010. Blubber thickness in both males and females declined at low per capita prey availability, and in breeding-age females, pregnancy rate declined at low blubber thickness, demonstrating a density-dependent response of pregnancy to prey limitation mediated through body condition. To the best of our knowledge, this is the first time a quantitative relationship among per capita prey abundance, body condition, and pregnancy rate has been documented for whales. As long-lived predators, marine mammals can act as indicators of the state of marine ecosystems. Improving our understanding of the relationships that link prey, body condition, and population parameters such as pregnancy rate and survival will become increasingly useful as these systems are affected by natural and anthropogenic change. Quantifying linkages among prey, fitness and vital rates will improve our ability to predict population consequences of subtle, sublethal impacts of ocean noise and other anthropogenic stressors.Changes in dive behaviour during naval sonar exposure in killer whales, long-finned pilot whales, and sperm whales.http://hdl.handle.net/10023/3851
Anthropogenic underwater sound in the environment might potentially affect the behavior of marine mammals enough to have an impact on their reproduction and survival. Diving behavior of four killer whales (Orcinus orca), seven long-finned pilot whales (Globicephala melas), and four sperm whales (Physeter macrocephalus) was studied during controlled exposures to naval sonar [low frequency active sonar (LFAS): 1–2 kHz and mid frequency active sonar (MFAS): 6–7 kHz] during three field seasons (2006–2009). Diving behavior was monitored before, during and after sonar exposure using an archival tag placed on the animal with suction cups. The tag recorded the animal's vertical movement, and additional data on horizontal movement and vocalizations were used to determine behavioral modes. Killer whales that were conducting deep dives at sonar onset changed abruptly to shallow diving (ShD) during LFAS, while killer whales conducting deep dives at the onset of MFAS did not alter dive mode. When in ShD mode at sonar onset, killer whales did not change their diving behavior. Pilot and sperm whales performed normal deep dives (NDD) during MFAS exposure. During LFAS exposures, long-finned pilot whales mostly performed fewer deep dives and some sperm whales performed shallower and shorter dives. Acoustic recording data presented previously indicates that deep diving (DD) is associated with feeding. Therefore, the observed changes in dive behavior of the three species could potentially reduce the foraging efficiency of the affected animals.
Thu, 11 Oct 2012 00:00:00 GMThttp://hdl.handle.net/10023/38512012-10-11T00:00:00ZSivle, Lise DKvadsheim, Petter HFahlman, AndreasLam, Frans PeterTyack, Peter LloydMiller, PatrickAnthropogenic underwater sound in the environment might potentially affect the behavior of marine mammals enough to have an impact on their reproduction and survival. Diving behavior of four killer whales (Orcinus orca), seven long-finned pilot whales (Globicephala melas), and four sperm whales (Physeter macrocephalus) was studied during controlled exposures to naval sonar [low frequency active sonar (LFAS): 1–2 kHz and mid frequency active sonar (MFAS): 6–7 kHz] during three field seasons (2006–2009). Diving behavior was monitored before, during and after sonar exposure using an archival tag placed on the animal with suction cups. The tag recorded the animal's vertical movement, and additional data on horizontal movement and vocalizations were used to determine behavioral modes. Killer whales that were conducting deep dives at sonar onset changed abruptly to shallow diving (ShD) during LFAS, while killer whales conducting deep dives at the onset of MFAS did not alter dive mode. When in ShD mode at sonar onset, killer whales did not change their diving behavior. Pilot and sperm whales performed normal deep dives (NDD) during MFAS exposure. During LFAS exposures, long-finned pilot whales mostly performed fewer deep dives and some sperm whales performed shallower and shorter dives. Acoustic recording data presented previously indicates that deep diving (DD) is associated with feeding. Therefore, the observed changes in dive behavior of the three species could potentially reduce the foraging efficiency of the affected animals.Blue whales respond to simulated mid-frequency military sonarhttp://hdl.handle.net/10023/3837
Mid-frequency military (1–10 kHz) sonars have been associated with lethal mass strandings of deep-diving toothed whales, but the effects on endangered baleen whale species are virtually unknown. Here, we used controlled exposure experiments with simulated military sonar and other mid-frequency sounds to measure behavioural responses of tagged blue whales (Balaenoptera musculus) in feeding areas within the Southern California Bight. Despite using source levels orders of magnitude below some operational military systems, our results demonstrate that mid-frequency sound can significantly affect blue whale behaviour, especially during deep feeding modes. When a response occurred, behavioural changes varied widely from cessation of deep feeding to increased swimming speed and directed travel away from the sound source. The variability of these behavioural responses was largely influenced by a complex interaction of behavioural state, the type of mid-frequency sound and received sound level. Sonar-induced disruption of feeding and displacement from high-quality prey patches could have significant and previously undocumented impacts on baleen whale foraging ecology, individual fitness and population health.
Tue, 01 Jan 2013 00:00:00 GMThttp://hdl.handle.net/10023/38372013-01-01T00:00:00ZGoldbogen, Jeremy A.Southall, Brandon L.De Ruiter, Stacy LynnCalambokidis, JohnFriedlaender, Ari S.Hazen, Elliott L.Falcone, Erin A.Schorr, Gregory S.Douglas, AnnieMoretti, David J.Kyburg, ChrisMcKenna, Megan F.Tyack, Peter LloydMid-frequency military (1–10 kHz) sonars have been associated with lethal mass strandings of deep-diving toothed whales, but the effects on endangered baleen whale species are virtually unknown. Here, we used controlled exposure experiments with simulated military sonar and other mid-frequency sounds to measure behavioural responses of tagged blue whales (Balaenoptera musculus) in feeding areas within the Southern California Bight. Despite using source levels orders of magnitude below some operational military systems, our results demonstrate that mid-frequency sound can significantly affect blue whale behaviour, especially during deep feeding modes. When a response occurred, behavioural changes varied widely from cessation of deep feeding to increased swimming speed and directed travel away from the sound source. The variability of these behavioural responses was largely influenced by a complex interaction of behavioural state, the type of mid-frequency sound and received sound level. Sonar-induced disruption of feeding and displacement from high-quality prey patches could have significant and previously undocumented impacts on baleen whale foraging ecology, individual fitness and population health.First direct measurements of behavioural responses by Cuvier's beaked whales to mid-frequency active sonarhttp://hdl.handle.net/10023/3836
Most marine mammal­ strandings coincident with naval sonar exercises have involved Cuvier's beaked whales (Ziphius cavirostris). We recorded animal movement and acoustic data on two tagged Ziphius and obtained the first direct measurements of behavioural responses of this species to mid-frequency active (MFA) sonar signals. Each recording included a 30-min playback (one 1.6-s simulated MFA sonar signal repeated every 25 s); one whale was also incidentally exposed to MFA sonar from distant naval exercises. Whales responded strongly to playbacks at low received levels (RLs; 89–127 dB re 1 µPa): after ceasing normal fluking and echolocation, they swam rapidly, silently away, extending both dive duration and subsequent non-foraging interval. Distant sonar exercises (78–106 dB re 1 µPa) did not elicit such responses, suggesting that context may moderate reactions. The observed responses to playback occurred at RLs well below current regulatory thresholds; equivalent responses to operational sonars could elevate stranding risk and reduce foraging efficiency.
Tue, 01 Jan 2013 00:00:00 GMThttp://hdl.handle.net/10023/38362013-01-01T00:00:00ZDe Ruiter, Stacy LynnSouthall, Brandon L.Calambokidis, JohnZimmer, Walter M. X.Sadykova, DinaraFalcone, Erin A.Friedlaender, Ari S.Joseph, John E.Moretti, DavidSchorr, Gregory S.Thomas, LenTyack, Peter LloydMost marine mammal­ strandings coincident with naval sonar exercises have involved Cuvier's beaked whales (Ziphius cavirostris). We recorded animal movement and acoustic data on two tagged Ziphius and obtained the first direct measurements of behavioural responses of this species to mid-frequency active (MFA) sonar signals. Each recording included a 30-min playback (one 1.6-s simulated MFA sonar signal repeated every 25 s); one whale was also incidentally exposed to MFA sonar from distant naval exercises. Whales responded strongly to playbacks at low received levels (RLs; 89–127 dB re 1 µPa): after ceasing normal fluking and echolocation, they swam rapidly, silently away, extending both dive duration and subsequent non-foraging interval. Distant sonar exercises (78–106 dB re 1 µPa) did not elicit such responses, suggesting that context may moderate reactions. The observed responses to playback occurred at RLs well below current regulatory thresholds; equivalent responses to operational sonars could elevate stranding risk and reduce foraging efficiency.Estimating animal population density using passive acousticshttp://hdl.handle.net/10023/3496
Reliable estimation of the size or density of wild animal populations is very important for effective wildlife management, conservation and ecology. Currently, the most widely used methods for obtaining such estimates involve either sighting animals from transect lines or some form of capture-recapture on marked or uniquely identifiable individuals. However, many species are difficult to sight, and cannot be easily marked or recaptured. Some of these species produce readily identifiable sounds, providing an opportunity to use passive acoustic data to estimate animal density. In addition, even for species for which other visually based methods are feasible, passive acoustic methods offer the potential for greater detection ranges in some environments (e.g. underwater or in dense forest), and hence potentially better precision. Automated data collection means that surveys can take place at times and in places where it would be too expensive or dangerous to send human observers. Here, we present an overview of animal density estimation using passive acoustic data, a relatively new and fast-developing field. We review the types of data and methodological approaches currently available to researchers and we provide a framework for acoustics-based density estimation, illustrated with examples from real-world case studies. We mention moving sensor platforms (e.g. towed acoustics), but then focus on methods involving sensors at fixed locations, particularly hydrophones to survey marine mammals, as acoustic-based density estimation research to date has been concentrated in this area. Primary among these are methods based on distance sampling and spatially explicit capture-recapture. The methods are also applicable to other aquatic and terrestrial sound-producing taxa. We conclude that, despite being in its infancy, density estimation based on passive acoustic data likely will become an important method for surveying a number of diverse taxa, such as sea mammals, fish, birds, amphibians, and insects, especially in situations where inferences are required over long periods of time. There is considerable work ahead, with several potentially fruitful research areas, including the development of (i) hardware and software for data acquisition, (ii) efficient, calibrated, automated detection and classification systems, and (iii) statistical approaches optimized for this application. Further, survey design will need to be developed, and research is needed on the acoustic behaviour of target species. Fundamental research on vocalization rates and group sizes, and the relation between these and other factors such as season or behaviour state, is critical. Evaluation of the methods under known density scenarios will be important for empirically validating the approaches presented here
Wed, 01 May 2013 00:00:00 GMThttp://hdl.handle.net/10023/34962013-05-01T00:00:00ZMarques, Tiago A.Thomas, LenMartin, StephenMellinger, DavidWard, JessicaMoretti, DavidHarris, Danielle VeronicaTyack, Peter LloydReliable estimation of the size or density of wild animal populations is very important for effective wildlife management, conservation and ecology. Currently, the most widely used methods for obtaining such estimates involve either sighting animals from transect lines or some form of capture-recapture on marked or uniquely identifiable individuals. However, many species are difficult to sight, and cannot be easily marked or recaptured. Some of these species produce readily identifiable sounds, providing an opportunity to use passive acoustic data to estimate animal density. In addition, even for species for which other visually based methods are feasible, passive acoustic methods offer the potential for greater detection ranges in some environments (e.g. underwater or in dense forest), and hence potentially better precision. Automated data collection means that surveys can take place at times and in places where it would be too expensive or dangerous to send human observers. Here, we present an overview of animal density estimation using passive acoustic data, a relatively new and fast-developing field. We review the types of data and methodological approaches currently available to researchers and we provide a framework for acoustics-based density estimation, illustrated with examples from real-world case studies. We mention moving sensor platforms (e.g. towed acoustics), but then focus on methods involving sensors at fixed locations, particularly hydrophones to survey marine mammals, as acoustic-based density estimation research to date has been concentrated in this area. Primary among these are methods based on distance sampling and spatially explicit capture-recapture. The methods are also applicable to other aquatic and terrestrial sound-producing taxa. We conclude that, despite being in its infancy, density estimation based on passive acoustic data likely will become an important method for surveying a number of diverse taxa, such as sea mammals, fish, birds, amphibians, and insects, especially in situations where inferences are required over long periods of time. There is considerable work ahead, with several potentially fruitful research areas, including the development of (i) hardware and software for data acquisition, (ii) efficient, calibrated, automated detection and classification systems, and (iii) statistical approaches optimized for this application. Further, survey design will need to be developed, and research is needed on the acoustic behaviour of target species. Fundamental research on vocalization rates and group sizes, and the relation between these and other factors such as season or behaviour state, is critical. Evaluation of the methods under known density scenarios will be important for empirically validating the approaches presented hereCompeting conservation objectives for predators and prey : estimating killer whale prey requirements for Chinook salmonhttp://hdl.handle.net/10023/3456
Ecosystem-based management (EBM) of marine resources attempts to conserve interacting species. In contrast to single-species fisheries management, EBM aims to identify and resolve conflicting objectives for different species. Such a conflict may be emerging in the northeastern Pacific for southern resident killer whales (Orcinus orca) and their primary prey, Chinook salmon (Oncorhynchus tshawytscha). Both species have at-risk conservation status and transboundary (Canada–US) ranges. We modeled individual killer whale prey requirements from feeding and growth records of captive killer whales and morphometric data from historic live-capture fishery and whaling records worldwide. The models, combined with caloric value of salmon, and demographic and diet data for wild killer whales, allow us to predict salmon quantities needed to maintain and recover this killer whale population, which numbered 87 individuals in 2009. Our analyses provide new information on cost of lactation and new parameter estimates for other killer whale populations globally. Prey requirements of southern resident killer whales are difficult to reconcile with fisheries and conservation objectives for Chinook salmon, because the number of fish required is large relative to annual returns and fishery catches. For instance, a U.S. recovery goal (2.3% annual population growth of killer whales over 28 years) implies a 75% increase in energetic requirements. Reducing salmon fisheries may serve as a temporary mitigation measure to allow time for management actions to improve salmon productivity to take effect. As ecosystem-based fishery management becomes more prevalent, trade-offs between conservation objectives for predators and prey will become increasingly necessary. Our approach offers scenarios to compare relative influence of various sources of uncertainty on the resulting consumption estimates to prioritise future research efforts, and a general approach for assessing the extent of conflict between conservation objectives for threatened or protected wildlife where the interaction between affected species can be quantified.
Wed, 09 Nov 2011 00:00:00 GMThttp://hdl.handle.net/10023/34562011-11-09T00:00:00ZWilliams, RobertKrkošek, MartinAshe, ErinBranch, Trevor AClark, StephenHammond, Philip StevenHoyt, EricNoren, Dawn PRosen, DavidWinship, ArlissEcosystem-based management (EBM) of marine resources attempts to conserve interacting species. In contrast to single-species fisheries management, EBM aims to identify and resolve conflicting objectives for different species. Such a conflict may be emerging in the northeastern Pacific for southern resident killer whales (Orcinus orca) and their primary prey, Chinook salmon (Oncorhynchus tshawytscha). Both species have at-risk conservation status and transboundary (Canada–US) ranges. We modeled individual killer whale prey requirements from feeding and growth records of captive killer whales and morphometric data from historic live-capture fishery and whaling records worldwide. The models, combined with caloric value of salmon, and demographic and diet data for wild killer whales, allow us to predict salmon quantities needed to maintain and recover this killer whale population, which numbered 87 individuals in 2009. Our analyses provide new information on cost of lactation and new parameter estimates for other killer whale populations globally. Prey requirements of southern resident killer whales are difficult to reconcile with fisheries and conservation objectives for Chinook salmon, because the number of fish required is large relative to annual returns and fishery catches. For instance, a U.S. recovery goal (2.3% annual population growth of killer whales over 28 years) implies a 75% increase in energetic requirements. Reducing salmon fisheries may serve as a temporary mitigation measure to allow time for management actions to improve salmon productivity to take effect. As ecosystem-based fishery management becomes more prevalent, trade-offs between conservation objectives for predators and prey will become increasingly necessary. Our approach offers scenarios to compare relative influence of various sources of uncertainty on the resulting consumption estimates to prioritise future research efforts, and a general approach for assessing the extent of conflict between conservation objectives for threatened or protected wildlife where the interaction between affected species can be quantified.Photo-grammetric measurements of swimming speed and body length of basking sharks observed around the Hebrides, Scotlandhttp://hdl.handle.net/10023/3445
Photo-grammetric techniques developed for measuring body length and small scale movement patterns of cetaceans were applied to surface swimming basking sharks off the west coast of Scotland. These methods removed the need for close approaches, reducing the likelihood of disturbing the focal animal. Average swimming speed was calculated from the total path length between shark locations measured at approximately one minute intervals. These average speeds varied from 0.49 to 0.73 ms−1 for tracks of between 30 and 170 minutes' duration. Body length measurements ranged between 2.35 and 6.43 m. For ten sharks where body length and swimming speed were measured there was a significant correlation between body length (L) and swimming speed (V) expressed as V = 0.36L033.
This work was funded and conducted by the International Fund for Animal Welfare.
Mon, 01 Mar 2010 00:00:00 GMThttp://hdl.handle.net/10023/34452010-03-01T00:00:00ZLacey, ClaireLeaper, RussellMoscrop, AnnaGillespie, Douglas MichaelMcLanaghan, RichardBrown, StevePhoto-grammetric techniques developed for measuring body length and small scale movement patterns of cetaceans were applied to surface swimming basking sharks off the west coast of Scotland. These methods removed the need for close approaches, reducing the likelihood of disturbing the focal animal. Average swimming speed was calculated from the total path length between shark locations measured at approximately one minute intervals. These average speeds varied from 0.49 to 0.73 ms−1 for tracks of between 30 and 170 minutes' duration. Body length measurements ranged between 2.35 and 6.43 m. For ten sharks where body length and swimming speed were measured there was a significant correlation between body length (L) and swimming speed (V) expressed as V = 0.36L033.To ping or not to ping : the use of active acoustic devices in mitigating interactions between small cetaceans and gillnet fisherieshttp://hdl.handle.net/10023/3394
Active sound emitters (‘pingers’) are used in several gillnet fisheries to reduce bycatch of small cetaceans, and/or to reduce depredation by dolphins. Here, we review studies conducted to determine how effective these devices may be as management tools. Significant reductions in bycatch of harbour porpoise Phocoena phocoena, franciscana Pontoporia blainvillei, common Delphinus delphis and striped dolphin Stenella coeruleoalba, and beaked whales as a group have been demonstrated. For harbour porpoise this result has been replicated in 14 controlled experiments in North America and Europe, and appears to be due to porpoises avoiding the area ensonified by pingers. Two gillnet fisheries (California-Oregon driftnet fishery for swordfish; New England groundfish fishery) with mandatory pinger use have been studied for over a decade. Bycatch rates of dolphins/porpoises have fallen by 50 to 60%, and there is no evidence of bycatch increasing over time due to habituation. In both fisheries, bycatch rates were significantly higher in nets sparsely equipped with pingers or in which pingers had failed, than in nets without any pingers at all. Studies of pinger use to reduce depredation by bottlenose dolphins Tursiops truncatus generally show small and inconsistent improvements in fish catches and somewhat reduced net damage. Dolphin bycatch in these fisheries is rare, but still occurs in nets with pingers. Taken together, these studies suggest that the most promising candidates for bycatch reduction via pinger use will be gillnet fisheries in developed countries in which the bycaught cetaceans are generally neophobic species with large home ranges. We offer a set of lessons learned from the last decade of bycatch management.
Tue, 01 Jan 2013 00:00:00 GMThttp://hdl.handle.net/10023/33942013-01-01T00:00:00ZDawson, SteveNorthridge, Simon PatrickWaples, DanielleRead, AndrewActive sound emitters (‘pingers’) are used in several gillnet fisheries to reduce bycatch of small cetaceans, and/or to reduce depredation by dolphins. Here, we review studies conducted to determine how effective these devices may be as management tools. Significant reductions in bycatch of harbour porpoise Phocoena phocoena, franciscana Pontoporia blainvillei, common Delphinus delphis and striped dolphin Stenella coeruleoalba, and beaked whales as a group have been demonstrated. For harbour porpoise this result has been replicated in 14 controlled experiments in North America and Europe, and appears to be due to porpoises avoiding the area ensonified by pingers. Two gillnet fisheries (California-Oregon driftnet fishery for swordfish; New England groundfish fishery) with mandatory pinger use have been studied for over a decade. Bycatch rates of dolphins/porpoises have fallen by 50 to 60%, and there is no evidence of bycatch increasing over time due to habituation. In both fisheries, bycatch rates were significantly higher in nets sparsely equipped with pingers or in which pingers had failed, than in nets without any pingers at all. Studies of pinger use to reduce depredation by bottlenose dolphins Tursiops truncatus generally show small and inconsistent improvements in fish catches and somewhat reduced net damage. Dolphin bycatch in these fisheries is rare, but still occurs in nets with pingers. Taken together, these studies suggest that the most promising candidates for bycatch reduction via pinger use will be gillnet fisheries in developed countries in which the bycaught cetaceans are generally neophobic species with large home ranges. We offer a set of lessons learned from the last decade of bycatch management.Seasonal inflow of warm water onto the southern Weddell Sea continental shelf, Antarcticahttp://hdl.handle.net/10023/3370
To capture the austral summer to winter transition in water mass properties over the southern Weddell Sea continental shelf and slope region Weddell seals were tagged with miniaturized conductivity–temperature–depth sensors in February 2011. During the following 8 months the instruments yielded about 9000 temperature–salinity profiles from a previously undersampled area. This allows, for the first time, a description of the seasonality of warm water intrusions onto the shelf. A temperature section across the Filchner Depression and eastern shelf shows a pronounced decrease in warm water inflow from summer to winter, further supported by an almost 3–year long time series from a shelf–break mooring. The seasonal variability is related to the surface wind stress and an associated deepening of the off–shore core of Warm Deep Water.
Sat, 01 Sep 2012 00:00:00 GMThttp://hdl.handle.net/10023/33702012-09-01T00:00:00ZArthun, MariusNicholls, KeithMakinson, KeithFedak, MikeBoehme, LarsTo capture the austral summer to winter transition in water mass properties over the southern Weddell Sea continental shelf and slope region Weddell seals were tagged with miniaturized conductivity–temperature–depth sensors in February 2011. During the following 8 months the instruments yielded about 9000 temperature–salinity profiles from a previously undersampled area. This allows, for the first time, a description of the seasonality of warm water intrusions onto the shelf. A temperature section across the Filchner Depression and eastern shelf shows a pronounced decrease in warm water inflow from summer to winter, further supported by an almost 3–year long time series from a shelf–break mooring. The seasonal variability is related to the surface wind stress and an associated deepening of the off–shore core of Warm Deep Water.Vocal copying of individually distinctive signature whistles in bottlenose dolphinshttp://hdl.handle.net/10023/3361
Vocal learning is relatively common in birds but less so in mammals. Sexual selection and individual or group recognition have been identified as major forces in its evolution. While important in the development of vocal displays, vocal learning also allows signal copying in social interactions. Such copying can function in addressing or labelling selected conspecifics. Most examples of addressing in non-humans come from bird song, where matching occurs in an aggressive context. However, in other animals, addressing with learned signals is very much an affiliative signal. We studied the function of vocal copying in a mammal that shows vocal learning as well as complex cognitive and social behaviour, the bottlenose dolphin (Tursiops truncatus). Copying occurred almost exclusively between close associates such as mother–calf pairs and male alliances during separation and was not followed by aggression. All copies were clearly recognizable as such because copiers consistently modified some acoustic parameters of a signal when copying it. We found no evidence for the use of copying in aggression or deception. This use of vocal copying is similar to its use in human language, where the maintenance of social bonds appears to be more important than the immediate defence of resources.
Mon, 22 Apr 2013 00:00:00 GMThttp://hdl.handle.net/10023/33612013-04-22T00:00:00ZKing, Stephanie LauraSayigh, LaelaWells, RandallFellner, WendiJanik, VincentVocal learning is relatively common in birds but less so in mammals. Sexual selection and individual or group recognition have been identified as major forces in its evolution. While important in the development of vocal displays, vocal learning also allows signal copying in social interactions. Such copying can function in addressing or labelling selected conspecifics. Most examples of addressing in non-humans come from bird song, where matching occurs in an aggressive context. However, in other animals, addressing with learned signals is very much an affiliative signal. We studied the function of vocal copying in a mammal that shows vocal learning as well as complex cognitive and social behaviour, the bottlenose dolphin (Tursiops truncatus). Copying occurred almost exclusively between close associates such as mother–calf pairs and male alliances during separation and was not followed by aggression. All copies were clearly recognizable as such because copiers consistently modified some acoustic parameters of a signal when copying it. We found no evidence for the use of copying in aggression or deception. This use of vocal copying is similar to its use in human language, where the maintenance of social bonds appears to be more important than the immediate defence of resources.Multispecies functional response of the minke whale Balaenoptera acutorostrata based on small-scale foraging studieshttp://hdl.handle.net/10023/3345
Atlantic minke whales are important predators in the Barents Sea ecosystem; capelin Mallotus villosus, krill Thysanoessa sp. and Meganyctephanes norvegica and herring Clupea harengus are their major prey. Their consumption of commercial species may present an economic problem for the local fishery. In order to estimate this consumption and understand the potential consequences for prey dynamics, it is essential to determine the multispecies functional response of the whales. The parameterisation of a functional response requires measurements of consumption rates and prey availability. In this localised study, undigested stomach contents were used to assess the amount of each prey that had been consumed immediately prior to capture. To determine the availability of prey to the whales, standard acoustic surveys were run in the same area within 2 d of the capture of the whales. The spatial distribution of prey was modelled using generalised additive models (GAMs). In order to generate a measure of prey availability and the uncertainty in this value, a simple model was assumed for whale movement, and prey abundance was sampled over space according to a Gaussian kernel. A multispecies functional response (MSFR) model was then fitted to the consumption and prey availability data using Bayesian methods. Simple simulations, based on the fitted MSFR, indicate that minke whales may deplete local capelin aggregations at small spatial scales. This is the first time that a multispecies functional response has been fitted for a cetacean predator, and the methods outlined here may prove useful for modelling marine mammal-fish interactions in other systems.
Sun, 01 Jul 2007 00:00:00 GMThttp://hdl.handle.net/10023/33452007-07-01T00:00:00ZSmout, Sophie CarolineLindstrom, UlfAtlantic minke whales are important predators in the Barents Sea ecosystem; capelin Mallotus villosus, krill Thysanoessa sp. and Meganyctephanes norvegica and herring Clupea harengus are their major prey. Their consumption of commercial species may present an economic problem for the local fishery. In order to estimate this consumption and understand the potential consequences for prey dynamics, it is essential to determine the multispecies functional response of the whales. The parameterisation of a functional response requires measurements of consumption rates and prey availability. In this localised study, undigested stomach contents were used to assess the amount of each prey that had been consumed immediately prior to capture. To determine the availability of prey to the whales, standard acoustic surveys were run in the same area within 2 d of the capture of the whales. The spatial distribution of prey was modelled using generalised additive models (GAMs). In order to generate a measure of prey availability and the uncertainty in this value, a simple model was assumed for whale movement, and prey abundance was sampled over space according to a Gaussian kernel. A multispecies functional response (MSFR) model was then fitted to the consumption and prey availability data using Bayesian methods. Simple simulations, based on the fitted MSFR, indicate that minke whales may deplete local capelin aggregations at small spatial scales. This is the first time that a multispecies functional response has been fitted for a cetacean predator, and the methods outlined here may prove useful for modelling marine mammal-fish interactions in other systems.Estimating demographic parameters for capture-recapture data in the presence of multiple mark typeshttp://hdl.handle.net/10023/3344
In mark-recapture studies, various techniques can be used to uniquely identify individual animals, such as ringing, tagging or photo-identification using natural markings. In some long-term studies more than one type of marking procedure may be implemented during the study period. In these circumstances, ignoring the different mark types can produce biased survival estimates since the assumption that the different mark types are equally catchable (homogeneous capture probability across mark types) may be incorrect.We implement an integrated approach where we simultaneously analyse data obtained using three different marking techniques, assuming that animals can be cross-classified across the different mark types. We discriminate between competing models using the AIC statistic. This technique also allows us to estimate both relative mark-loss probabilities and relative recapture efficiency rates for the different marking methods.We initially perform a simulation study to explore the different biases that can be introduced if we assume a homogeneous recapture probability over mark type, before applying the method to a real dataset. We make use of data obtained from an intensive long-term observational study of UK female grey seals (Halichoerus grypus) at a single breeding colony, where three different methods are used to identify individuals within a single study: branding, tagging and photo-identification based on seal coat pattern or pelage.
Wed, 01 Jun 2011 00:00:00 GMThttp://hdl.handle.net/10023/33442011-06-01T00:00:00ZSmout, Sophie CarolineKing, RuthPomeroy, PatrickIn mark-recapture studies, various techniques can be used to uniquely identify individual animals, such as ringing, tagging or photo-identification using natural markings. In some long-term studies more than one type of marking procedure may be implemented during the study period. In these circumstances, ignoring the different mark types can produce biased survival estimates since the assumption that the different mark types are equally catchable (homogeneous capture probability across mark types) may be incorrect.We implement an integrated approach where we simultaneously analyse data obtained using three different marking techniques, assuming that animals can be cross-classified across the different mark types. We discriminate between competing models using the AIC statistic. This technique also allows us to estimate both relative mark-loss probabilities and relative recapture efficiency rates for the different marking methods.We initially perform a simulation study to explore the different biases that can be introduced if we assume a homogeneous recapture probability over mark type, before applying the method to a real dataset. We make use of data obtained from an intensive long-term observational study of UK female grey seals (Halichoerus grypus) at a single breeding colony, where three different methods are used to identify individuals within a single study: branding, tagging and photo-identification based on seal coat pattern or pelage.How many seals were there? The global shelf loss during the Last Glacial Maximum and its effect on the size and distribution of grey seal populationshttp://hdl.handle.net/10023/3315
Predicting how marine mammal populations act to habitat changes will be essential for developing conservation management strategies by marine mammal ecologists in the 21st century. Responses to previous environmental change may be informative in the development of predictive models. Here we describe the likely effects of the last ice age on grey seal population size and distribution. We use satellite telemetry data to define grey seal foraging habitat in terms of the temperature and depth ranges exploited by the contemporary populations. We estimate the available extent of such habitat in the North Atlantic at present and at the last glacial maximum (LGM); taking account of glacial and seasonal sea-ice coverage, estimated reductions of sea-level (123m) and seawater temperature hind-casts from GLAMAP-2000. Most of the extensive continental shelf waters (North Sea, Baltic Sea and Scotian Shelf), currently supporting >95% of grey seals, were unavailable at the LGM. A combination of lower sea-level and extensive ice-sheets, massively increased seasonal sea-ice coverage and southerly extent of cold water would have pushed grey seals into areas with no significant shelf waters. The habitat during the LGM might have been as small as 4%, when compared to today’s extent and grey seal populations may have fallen to similarly. An alternative scenario involving a major change to a pelagic/bathy-pelagic foraging niche cannot be discounted. However, hooded seals that appear to out-compete and effectively exclude grey seals from such habitat currently dominate that niche. If as seems likely, the grey seal population fell to very low levels it would have remained low for several thousand years before expanding into current habitats over the last 12000 years or so.
The tagging studies were funded by the Natural Environment Research Council, UK; the Atlantic seal research program, Department of Fisheries and Oceans, Canada and NSERCD Discovery grants, Canada. This work also received funding from the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland) and their support is gratefully acknowledged. MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Wed, 26 Dec 2012 00:00:00 GMThttp://hdl.handle.net/10023/33152012-12-26T00:00:00ZBoehme, LarsThompson, DavidFedak, MikeBowen, DonHammill, MikeStenson, GaryPredicting how marine mammal populations act to habitat changes will be essential for developing conservation management strategies by marine mammal ecologists in the 21st century. Responses to previous environmental change may be informative in the development of predictive models. Here we describe the likely effects of the last ice age on grey seal population size and distribution. We use satellite telemetry data to define grey seal foraging habitat in terms of the temperature and depth ranges exploited by the contemporary populations. We estimate the available extent of such habitat in the North Atlantic at present and at the last glacial maximum (LGM); taking account of glacial and seasonal sea-ice coverage, estimated reductions of sea-level (123m) and seawater temperature hind-casts from GLAMAP-2000. Most of the extensive continental shelf waters (North Sea, Baltic Sea and Scotian Shelf), currently supporting >95% of grey seals, were unavailable at the LGM. A combination of lower sea-level and extensive ice-sheets, massively increased seasonal sea-ice coverage and southerly extent of cold water would have pushed grey seals into areas with no significant shelf waters. The habitat during the LGM might have been as small as 4%, when compared to today’s extent and grey seal populations may have fallen to similarly. An alternative scenario involving a major change to a pelagic/bathy-pelagic foraging niche cannot be discounted. However, hooded seals that appear to out-compete and effectively exclude grey seals from such habitat currently dominate that niche. If as seems likely, the grey seal population fell to very low levels it would have remained low for several thousand years before expanding into current habitats over the last 12000 years or so.Variation in female grey seal (Halichoerus grypus) reproductive performance correlates to proactive-reactive behavioural typeshttp://hdl.handle.net/10023/3314
Consistent individual differences (CIDs) in behaviour, indicative of behavioural types or personalities, have been shown in taxa ranging from Cnidaria to Mammalia. However, despite numerous theoretical explanations there remains limited empirical evidence for selective mechanisms that maintain such variation within natural populations. We examined behavioural types and fitness proxies in wild female grey seals at the North Rona breeding colony. Experiments in 2009 and 2010 employed a remotely-controlled vehicle to deliver a novel auditory stimulus to females to elicit changes in pup-checking behaviour. Mothers tested twice during lactation exhibited highly repeatable individual pup-checking rates within and across breeding seasons. Observations of undisturbed mothers (i.e. experiencing no disturbance from conspecifics or experimental test) also revealed CIDs in pup-checking behaviour. However, there was no correlation between an individuals’ pup-checking rate during undisturbed observations with the rate in response to the auditory test, indicating plasticity across situations. The extent to which individuals changed rates of pup-checking from undisturbed to disturbed conditions revealed a continuum of behavioural types from proactive females, who maintained a similar rate throughout, to reactive females, who increased pup-checking markedly in response to the test. Variation in maternal expenditure (daily mass loss rate) was greater among more reactive mothers than proactive mothers. Consequently pups of more reactive mothers had more varied growth rates centred around the long-term population mean. These patterns could not be accounted for by other measured covariates as behavioural type was unrelated to a mother’s prior experience, degree of inter-annual site fidelity, physical characteristics of their pupping habitat, pup sex or pup activity. These findings are consistent with the hypothesis that variation in behavioural types is maintained by spatial and temporal environmental variation combined with limits to phenotype-environment matching.
Fri, 16 Nov 2012 00:00:00 GMThttp://hdl.handle.net/10023/33142012-11-16T00:00:00ZTwiss, Sean DCairns, CharlotteCulloch, RossRichards, Shane APomeroy, PatrickConsistent individual differences (CIDs) in behaviour, indicative of behavioural types or personalities, have been shown in taxa ranging from Cnidaria to Mammalia. However, despite numerous theoretical explanations there remains limited empirical evidence for selective mechanisms that maintain such variation within natural populations. We examined behavioural types and fitness proxies in wild female grey seals at the North Rona breeding colony. Experiments in 2009 and 2010 employed a remotely-controlled vehicle to deliver a novel auditory stimulus to females to elicit changes in pup-checking behaviour. Mothers tested twice during lactation exhibited highly repeatable individual pup-checking rates within and across breeding seasons. Observations of undisturbed mothers (i.e. experiencing no disturbance from conspecifics or experimental test) also revealed CIDs in pup-checking behaviour. However, there was no correlation between an individuals’ pup-checking rate during undisturbed observations with the rate in response to the auditory test, indicating plasticity across situations. The extent to which individuals changed rates of pup-checking from undisturbed to disturbed conditions revealed a continuum of behavioural types from proactive females, who maintained a similar rate throughout, to reactive females, who increased pup-checking markedly in response to the test. Variation in maternal expenditure (daily mass loss rate) was greater among more reactive mothers than proactive mothers. Consequently pups of more reactive mothers had more varied growth rates centred around the long-term population mean. These patterns could not be accounted for by other measured covariates as behavioural type was unrelated to a mother’s prior experience, degree of inter-annual site fidelity, physical characteristics of their pupping habitat, pup sex or pup activity. These findings are consistent with the hypothesis that variation in behavioural types is maintained by spatial and temporal environmental variation combined with limits to phenotype-environment matching.Estimated tissue and blood N2 levels and risk of in vivo bubble formation in deep-, intermediate- and shallow diving toothed whales during exposure to naval sonar.http://hdl.handle.net/10023/3301
Naval sonar has been accused of causing whale stranding by a mechanism which increases formation of tissue N2 gas bubbles. Increased tissue and blood N2 levels, and thereby increased risk of decompression sickness (DCS), is thought to result from changes in behavior or physiological responses during diving. Previous theoretical studies have used hypothetical sonar-induced changes in both behavior and physiology to model blood and tissue N2 tension PN2, but this is the first attempt to estimate the changes during actual behavioral responses to sonar. We used an existing mathematical model to estimate blood and tissue N2 tension PN2 from dive data recorded from sperm, killer, long-finned pilot, Blainville’s beaked, and Cuvier’s beaked whales before and during exposure to Low- (1–2 kHz) and Mid- (2–7 kHz) frequency active sonar. Our objectives were: (1) to determine if differences in dive behavior affects risk of bubble formation, and if (2) behavioral- or (3) physiological responses to sonar are plausible risk factors. Our results suggest that all species have natural high N2 levels, with deep diving generally resulting in higher end-dive PN2 as compared with shallow diving. Sonar exposure caused some changes in dive behavior in both killer whales, pilot whales and beaked whales, but this did not lead to any increased risk of DCS. However, in three of eight exposure session with sperm whales, the animal changed to shallower diving, and in all these cases this seem to result in an increased risk of DCS, although risk was still within the normal risk range of this species. When a hypothetical removal of the normal dive response (bradycardia and peripheral vasoconstriction), was added to the behavioral response during model simulations, this led to an increased variance in the estimated end-dive N2 levels, but no consistent change of risk. In conclusion, we cannot rule out the possibility that a combination of behavioral and physiological responses to sonar have the potential to alter the blood and tissue end-dive N2 tension to levels which could cause DCS and formation of in vivo bubbles, but the actually observed behavioral responses of cetaceans to sonar in our study, do not imply any significantly increased risk of DCS.
Thu, 10 May 2012 00:00:00 GMThttp://hdl.handle.net/10023/33012012-05-10T00:00:00ZKvadsheim, Petter HMiller, PatrickTyack, Peter LloydSivle, Lise DLam, Frans PeterFahlman, AndreasNaval sonar has been accused of causing whale stranding by a mechanism which increases formation of tissue N2 gas bubbles. Increased tissue and blood N2 levels, and thereby increased risk of decompression sickness (DCS), is thought to result from changes in behavior or physiological responses during diving. Previous theoretical studies have used hypothetical sonar-induced changes in both behavior and physiology to model blood and tissue N2 tension PN2, but this is the first attempt to estimate the changes during actual behavioral responses to sonar. We used an existing mathematical model to estimate blood and tissue N2 tension PN2 from dive data recorded from sperm, killer, long-finned pilot, Blainville’s beaked, and Cuvier’s beaked whales before and during exposure to Low- (1–2 kHz) and Mid- (2–7 kHz) frequency active sonar. Our objectives were: (1) to determine if differences in dive behavior affects risk of bubble formation, and if (2) behavioral- or (3) physiological responses to sonar are plausible risk factors. Our results suggest that all species have natural high N2 levels, with deep diving generally resulting in higher end-dive PN2 as compared with shallow diving. Sonar exposure caused some changes in dive behavior in both killer whales, pilot whales and beaked whales, but this did not lead to any increased risk of DCS. However, in three of eight exposure session with sperm whales, the animal changed to shallower diving, and in all these cases this seem to result in an increased risk of DCS, although risk was still within the normal risk range of this species. When a hypothetical removal of the normal dive response (bradycardia and peripheral vasoconstriction), was added to the behavioral response during model simulations, this led to an increased variance in the estimated end-dive N2 levels, but no consistent change of risk. In conclusion, we cannot rule out the possibility that a combination of behavioral and physiological responses to sonar have the potential to alter the blood and tissue end-dive N2 tension to levels which could cause DCS and formation of in vivo bubbles, but the actually observed behavioral responses of cetaceans to sonar in our study, do not imply any significantly increased risk of DCS.The functional response of a generalist predatorhttp://hdl.handle.net/10023/3269
Background: Predators can have profound impacts on the dynamics of their prey that depend on how predator consumption is affected by prey density (the predator's functional response). Consumption by a generalist predator is expected to depend on the densities of all its major prey species (its multispecies functional response, or MSFR), but most studies of generalists have focussed on their functional response to only one prey species. Methodology and principal findings: Using Bayesian methods, we fit an MSFR to field data from an avian predator (the hen harrier Circus cyaneus) feeding on three different prey species. We use a simple graphical approach to show that ignoring the effects of alternative prey can give a misleading impression of the predator's effect on the prey of interest. For example, in our system, a “predator pit” for one prey species only occurs when the availability of other prey species is low. Conclusions and significance: The Bayesian approach is effective in fitting the MSFR model to field data. It allows flexibility in modelling over-dispersion, incorporates additional biological information into the parameter priors, and generates estimates of uncertainty in the model's predictions. These features of robustness and data efficiency make our approach ideal for the study of long-lived predators, for which data may be sparse and management/conservation priorities pressing.
Thu, 27 May 2010 00:00:00 GMThttp://hdl.handle.net/10023/32692010-05-27T00:00:00ZSmout, Sophie CarolineAsseburg, CMatthiopoulos, JasonFernández, CarmenRedpath, SThirgood, SHarwood, JohnBackground: Predators can have profound impacts on the dynamics of their prey that depend on how predator consumption is affected by prey density (the predator's functional response). Consumption by a generalist predator is expected to depend on the densities of all its major prey species (its multispecies functional response, or MSFR), but most studies of generalists have focussed on their functional response to only one prey species. Methodology and principal findings: Using Bayesian methods, we fit an MSFR to field data from an avian predator (the hen harrier Circus cyaneus) feeding on three different prey species. We use a simple graphical approach to show that ignoring the effects of alternative prey can give a misleading impression of the predator's effect on the prey of interest. For example, in our system, a “predator pit” for one prey species only occurs when the availability of other prey species is low. Conclusions and significance: The Bayesian approach is effective in fitting the MSFR model to field data. It allows flexibility in modelling over-dispersion, incorporates additional biological information into the parameter priors, and generates estimates of uncertainty in the model's predictions. These features of robustness and data efficiency make our approach ideal for the study of long-lived predators, for which data may be sparse and management/conservation priorities pressing.Repeated elicitation of the acoustic startle reflex leads to sensitisation in subsequent avoidance behaviour and induces fear conditioninghttp://hdl.handle.net/10023/3267
Background: Autonomous reflexes enable animals to respond quickly to potential threats, prevent injury and mediate fight or flight responses. Intense acoustic stimuli with sudden onsets elicit a startle reflex while stimuli of similar intensity but with longer rise times only cause a cardiac defence response. In laboratory settings, habituation appears to affect all of these reflexes so that the response amplitude generally decreases with repeated exposure to the stimulus. The startle reflex has become a model system for the study of the neural basis of simple learning processes and emotional processing and is often used as a diagnostic tool in medical applications. However, previous studies did not allow animals to avoid the stimulus and the evolutionary function and long-term behavioural consequences of repeated startling remain speculative. In this study we investigate the follow-up behaviour associated with the startle reflex in wild-captured animals using an experimental setup that allows individuals to exhibit avoidance behaviour. Results: We present evidence that repeated elicitation of the acoustic startle reflex leads to rapid and pronounced sensitisation of sustained spatial avoidance behaviour in grey seals (Halichoerus grypus). Animals developed rapid flight responses, left the exposure pool and showed clear signs of fear conditioning. Once sensitised, seals even avoided a known food source that was close to the sound source. In contrast, animals exposed to non-startling (long rise time) stimuli of the same maximum sound pressure habituated and flight responses waned or were absent from the beginning. The startle threshold of grey seals expressed in units of sensation levels was comparable to thresholds reported for other mammals (93 dB). Conclusions: Our results demonstrate that the acoustic startle reflex plays a crucial role in mediating flight responses and strongly influences the motivational state of an animal beyond a short-term muscular response by mediating long-term avoidance. The reflex is therefore not only a measure of emotional state but also influences emotional processing. The biological function of the startle reflex is most likely associated with mediating rapid flight responses. The data indicate that repeated startling by anthropogenic noise sources might have severe effects on long-term behaviour. Future, studies are needed to investigate whether such effects can be associated with reduced individual fitness or even longevity of individuals.
Sat, 01 Jan 2011 00:00:00 GMThttp://hdl.handle.net/10023/32672011-01-01T00:00:00ZGotz, ThomasJanik, VincentBackground: Autonomous reflexes enable animals to respond quickly to potential threats, prevent injury and mediate fight or flight responses. Intense acoustic stimuli with sudden onsets elicit a startle reflex while stimuli of similar intensity but with longer rise times only cause a cardiac defence response. In laboratory settings, habituation appears to affect all of these reflexes so that the response amplitude generally decreases with repeated exposure to the stimulus. The startle reflex has become a model system for the study of the neural basis of simple learning processes and emotional processing and is often used as a diagnostic tool in medical applications. However, previous studies did not allow animals to avoid the stimulus and the evolutionary function and long-term behavioural consequences of repeated startling remain speculative. In this study we investigate the follow-up behaviour associated with the startle reflex in wild-captured animals using an experimental setup that allows individuals to exhibit avoidance behaviour. Results: We present evidence that repeated elicitation of the acoustic startle reflex leads to rapid and pronounced sensitisation of sustained spatial avoidance behaviour in grey seals (Halichoerus grypus). Animals developed rapid flight responses, left the exposure pool and showed clear signs of fear conditioning. Once sensitised, seals even avoided a known food source that was close to the sound source. In contrast, animals exposed to non-startling (long rise time) stimuli of the same maximum sound pressure habituated and flight responses waned or were absent from the beginning. The startle threshold of grey seals expressed in units of sensation levels was comparable to thresholds reported for other mammals (93 dB). Conclusions: Our results demonstrate that the acoustic startle reflex plays a crucial role in mediating flight responses and strongly influences the motivational state of an animal beyond a short-term muscular response by mediating long-term avoidance. The reflex is therefore not only a measure of emotional state but also influences emotional processing. The biological function of the startle reflex is most likely associated with mediating rapid flight responses. The data indicate that repeated startling by anthropogenic noise sources might have severe effects on long-term behaviour. Future, studies are needed to investigate whether such effects can be associated with reduced individual fitness or even longevity of individuals.Vessel noise affects beaked whale behavior : Results of a dedicated acoustic response studyhttp://hdl.handle.net/10023/3078
Some beaked whale species are susceptible to the detrimental effects of anthropogenic noise. Most studies have concentrated on the effects of military sonar, but other forms of acoustic disturbance (e.g. shipping noise) may disrupt behavior. An experiment involving the exposure of target whale groups to intense vessel-generated noise tested how these exposures influenced the foraging behavior of Blainville’s beaked whales (Mesoplodon densirostris) in the Tongue of the Ocean (Bahamas). A military array of bottom-mounted hydrophones was used to measure the response based upon changes in the spatial and temporal pattern of vocalizations. The archived acoustic data were used to compute metrics the echolocation-based foraging behavior for 16 targeted groups, 10 groups further away on the range, and 26 nonexposed groups. The duration of foraging bouts was not significantly affected by the exposure. Changes in the hydrophone over which the group was most frequently detected occurred as the animals moved around within a foraging bout, and their number was significantly less the closer the whales were to the sound source. Non-exposed groups also had significantly more changes in the primary hydrophone than exposed groups irrespective of distance. Our results suggested that broadband ship noise caused a significant change in beaked whale behavior up to at least 5.2 kilometers away from the vessel. The observed change could potentially correspond to a restriction in the movement of groups, a period of more directional travel, a reduction in the number of individuals clicking within the group, or a response to changes in prey movement.
Fri, 03 Aug 2012 00:00:00 GMThttp://hdl.handle.net/10023/30782012-08-03T00:00:00ZPirotta, EnricoMilor, RachelQuick, Nicola JaneMoretti, DavidDimarzio, NancyTyack, Peter LloydBoyd, IanHastie, Gordon DrummondSome beaked whale species are susceptible to the detrimental effects of anthropogenic noise. Most studies have concentrated on the effects of military sonar, but other forms of acoustic disturbance (e.g. shipping noise) may disrupt behavior. An experiment involving the exposure of target whale groups to intense vessel-generated noise tested how these exposures influenced the foraging behavior of Blainville’s beaked whales (Mesoplodon densirostris) in the Tongue of the Ocean (Bahamas). A military array of bottom-mounted hydrophones was used to measure the response based upon changes in the spatial and temporal pattern of vocalizations. The archived acoustic data were used to compute metrics the echolocation-based foraging behavior for 16 targeted groups, 10 groups further away on the range, and 26 nonexposed groups. The duration of foraging bouts was not significantly affected by the exposure. Changes in the hydrophone over which the group was most frequently detected occurred as the animals moved around within a foraging bout, and their number was significantly less the closer the whales were to the sound source. Non-exposed groups also had significantly more changes in the primary hydrophone than exposed groups irrespective of distance. Our results suggested that broadband ship noise caused a significant change in beaked whale behavior up to at least 5.2 kilometers away from the vessel. The observed change could potentially correspond to a restriction in the movement of groups, a period of more directional travel, a reduction in the number of individuals clicking within the group, or a response to changes in prey movement.Spatial variation in foraging behaviour of a marine top predator (Phoca vitulina) determined by a large-scale satellite tagging programhttp://hdl.handle.net/10023/3076
The harbour seal (Phoca vitulina) is a widespread marine predator in Northern Hemisphere waters. British populations have been subject to rapid declines in recent years. Food supply or inter-specific competition may be implicated but basic ecological data are lacking and there are few studies of harbour seal foraging distribution and habits. In this study, satellite tagging conducted at the major seal haul outs around the British Isles showed both that seal movements were highly variable among individuals and that foraging strategy appears to be specialized within particular regions. We investigated whether these apparent differences could be explained by individual level factors: by modelling measures of trip duration and distance travelled as a function of size, sex and body condition. However, these were not found to be good predictors of foraging trip duration or distance, which instead was best predicted by tagging region, time of year and inter-trip duration. Therefore, we propose that local habitat conditions and the constraints they impose are the major determinants of foraging movements. Specifically the distance to profitable feeding grounds from suitable haul-out locations may dictate foraging strategy and behaviour. Accounting for proximity to productive foraging resources is likely to be an important component of understanding population processes. Despite more extensive offshore movements than expected, there was also marked fidelity to the local haul-out region with limited connectivity between study regions. These empirical observations of regional exchange at short time scales demonstrates the value of large scale electronic tagging programs for robust characterization of at-sea foraging behaviour at a wide spatial scale.
The work was supported by the United Kingdom Department of Trade and industry, now the Department of Energy and Climate Change (http://www. decc.gov.uk/) through its Strategic Environmental Assessment programme (http://www.offshore-sea. .uk). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Mon, 21 May 2012 00:00:00 GMThttp://hdl.handle.net/10023/30762012-05-21T00:00:00ZSharples, Ruth JemmaMoss, Simon EPatterson, Toby AHammond, Philip StevenThe harbour seal (Phoca vitulina) is a widespread marine predator in Northern Hemisphere waters. British populations have been subject to rapid declines in recent years. Food supply or inter-specific competition may be implicated but basic ecological data are lacking and there are few studies of harbour seal foraging distribution and habits. In this study, satellite tagging conducted at the major seal haul outs around the British Isles showed both that seal movements were highly variable among individuals and that foraging strategy appears to be specialized within particular regions. We investigated whether these apparent differences could be explained by individual level factors: by modelling measures of trip duration and distance travelled as a function of size, sex and body condition. However, these were not found to be good predictors of foraging trip duration or distance, which instead was best predicted by tagging region, time of year and inter-trip duration. Therefore, we propose that local habitat conditions and the constraints they impose are the major determinants of foraging movements. Specifically the distance to profitable feeding grounds from suitable haul-out locations may dictate foraging strategy and behaviour. Accounting for proximity to productive foraging resources is likely to be an important component of understanding population processes. Despite more extensive offshore movements than expected, there was also marked fidelity to the local haul-out region with limited connectivity between study regions. These empirical observations of regional exchange at short time scales demonstrates the value of large scale electronic tagging programs for robust characterization of at-sea foraging behaviour at a wide spatial scale.Global coverage of cetacean line-transect surveys : status quo, data gaps and future challengeshttp://hdl.handle.net/10023/3074
Knowledge of abundance, trends and distribution of cetacean populations is needed to inform marine conservation efforts, ecosystem models and spatial planning. We compiled a geo-spatial database of published data on cetacean abundance from dedicated visual line-transect surveys and encoded >1100 abundance estimates for 47 species from 430 surveys conducted worldwide from 1975-2005. Our subsequent analyses revealed large spatial, temporal and taxonomic variability and gaps in survey coverage. With the exception of Antarctic waters, survey coverage was biased toward the northern hemisphere, especially US and northern European waters. Overall, <25% of the world’s ocean surface was surveyed and only 6% had been covered frequently enough (≥ 5 times) to allow trend estimation. Almost half the global survey effort, defined as total area (km2) covered by all survey study areas across time, was concentrated in the Eastern Tropical Pacific (ETP). Neither the number of surveys conducted nor the survey effort had increased in recent years. Across species, an average of 10% of a species’ predicted range had been covered by at least one survey, but there was considerable variation among species. With the exception of three delphinid species, <1% of all species’ ranges had been covered frequently enough for trend analysis. We use a data-rich species, sperm whale, as an example to illustrate the challenges of using available data from line-transect surveys for the detection of trends or for spatial planning. Finally, we propose and contrast several field and analytical methods to fill in data gaps to improve future cetacean conservation management efforts.
Wed, 12 Sep 2012 00:00:00 GMThttp://hdl.handle.net/10023/30742012-09-12T00:00:00ZKaschner, KristinQuick, Nicola JaneJewell, Rebecca LucyWilliams, RobertHarris, Catriona MKnowledge of abundance, trends and distribution of cetacean populations is needed to inform marine conservation efforts, ecosystem models and spatial planning. We compiled a geo-spatial database of published data on cetacean abundance from dedicated visual line-transect surveys and encoded >1100 abundance estimates for 47 species from 430 surveys conducted worldwide from 1975-2005. Our subsequent analyses revealed large spatial, temporal and taxonomic variability and gaps in survey coverage. With the exception of Antarctic waters, survey coverage was biased toward the northern hemisphere, especially US and northern European waters. Overall, <25% of the world’s ocean surface was surveyed and only 6% had been covered frequently enough (≥ 5 times) to allow trend estimation. Almost half the global survey effort, defined as total area (km2) covered by all survey study areas across time, was concentrated in the Eastern Tropical Pacific (ETP). Neither the number of surveys conducted nor the survey effort had increased in recent years. Across species, an average of 10% of a species’ predicted range had been covered by at least one survey, but there was considerable variation among species. With the exception of three delphinid species, <1% of all species’ ranges had been covered frequently enough for trend analysis. We use a data-rich species, sperm whale, as an example to illustrate the challenges of using available data from line-transect surveys for the detection of trends or for spatial planning. Finally, we propose and contrast several field and analytical methods to fill in data gaps to improve future cetacean conservation management efforts.Phocid seal leptin : tertiary structure and hydrophobic receptor binding site preservation during distinct leptin gene evolutionhttp://hdl.handle.net/10023/3003
The cytokine hormone leptin is a key signalling molecule in many pathways that control physiological functions. Although leptin demonstrates structural conservation in mammals, there is evidence of positive selection in primates, lagomorphs and chiropterans. We previously reported that the leptin genes of the grey and harbour seals (phocids) have significantly diverged from other mammals. Therefore we further investigated the diversification of leptin in phocids, other marine mammals and terrestrial taxa by sequencing the leptin genes of representative species. Phylogenetic reconstruction revealed that leptin diversification was pronounced within the phocid seals with a high dN/dS ratio of 2.8, indicating positive selection. We found significant evidence of positive selection along the branch leading to the phocids, within the phocid clade, but not over the dataset as a whole. Structural predictions indicate that the individual residues under selection are away from the leptin receptor (LEPR) binding site. Predictions of the surface electrostatic potential indicate that phocid seal leptin is notably different to other mammalian leptins, including the otariids. Cloning the grey seal leptin binding domain of LEPR confirmed that this was structurally conserved. These data, viewed in toto, support a hypothesis that phocid leptin divergence is unlikely to have arisen by random mutation. Based upon these phylogenetic and structural assessments, and considering the comparative physiology and varying life histories among species, we postulate that the unique phocid diving behaviour has produced this selection pressure. The Phocidae includes some of the deepest diving species, yet have the least modified lung structure to cope with pressure and volume changes experienced at depth. Therefore, greater surfactant production is required to facilitate rapid lung re-inflation upon surfacing, while maintaining patent airways. We suggest that this additional surfactant requirement is met by the leptin pulmonary surfactant production pathway which normally appears only to function in the mammalian foetus.
This work was supported by funds from the UK Natural Environment Research Council
Thu, 19 Apr 2012 00:00:00 GMThttp://hdl.handle.net/10023/30032012-04-19T00:00:00ZHammond, John AnthonyHauton, ChrisBennett, Kimberley A.Hall, Ailsa JaneThe cytokine hormone leptin is a key signalling molecule in many pathways that control physiological functions. Although leptin demonstrates structural conservation in mammals, there is evidence of positive selection in primates, lagomorphs and chiropterans. We previously reported that the leptin genes of the grey and harbour seals (phocids) have significantly diverged from other mammals. Therefore we further investigated the diversification of leptin in phocids, other marine mammals and terrestrial taxa by sequencing the leptin genes of representative species. Phylogenetic reconstruction revealed that leptin diversification was pronounced within the phocid seals with a high dN/dS ratio of 2.8, indicating positive selection. We found significant evidence of positive selection along the branch leading to the phocids, within the phocid clade, but not over the dataset as a whole. Structural predictions indicate that the individual residues under selection are away from the leptin receptor (LEPR) binding site. Predictions of the surface electrostatic potential indicate that phocid seal leptin is notably different to other mammalian leptins, including the otariids. Cloning the grey seal leptin binding domain of LEPR confirmed that this was structurally conserved. These data, viewed in toto, support a hypothesis that phocid leptin divergence is unlikely to have arisen by random mutation. Based upon these phylogenetic and structural assessments, and considering the comparative physiology and varying life histories among species, we postulate that the unique phocid diving behaviour has produced this selection pressure. The Phocidae includes some of the deepest diving species, yet have the least modified lung structure to cope with pressure and volume changes experienced at depth. Therefore, greater surfactant production is required to facilitate rapid lung re-inflation upon surfacing, while maintaining patent airways. We suggest that this additional surfactant requirement is met by the leptin pulmonary surfactant production pathway which normally appears only to function in the mammalian foetus.Modeling distribution and abundance of Antarctic baleen whales using ships of opportunityhttp://hdl.handle.net/10023/2857
Information on animal abundance and distribution is at the cornerstone of many wildlife and conservation strategies. However, these data can be difficult and costly to obtain for cetacean species. The expense of sufficient ship time to conduct design-unbiased line transect surveys may be simply out of reach for researchers in many countries, which nonetheless grapple with problems of conservation of endangered species, by-catch of small cetaceans in commercial fisheries, and progression toward ecosystem-based fisheries management. Recently developed spatial modeling techniques show promise for estimating wildlife abundance using non-randomized surveys, but have yet to receive much field-testing in areas where designed surveys have also been conducted. Effort and sightings data were collected along 9 650 km of transects aboard ships of opportunity in the Southern Ocean during the austral summers of 2000 - 2001 and 2001 - 2002. Generalized additive models with generalized cross-validation were used to express heterogeneity of cetacean sightings as functions of spatial covariates. Models were used to map predicted densities and to estimate abundance of humpback, minke, and fin whales in the Drake Passage and along the Antarctic Peninsula. All species' distribution maps showed strong density gradients, which were robust to jackknife resampling when each of 14 trips was removed sequentially with replacement. Looped animations of model predictions of whale density illustrate uncertainty in distribution estimates in a way that is informative to non-scientists. The best abundance estimate for humpback whales was 1 829 (95% CI: 978- 3 422). Abundance of fin whales was 4 487 ( 95% CI: 1 326 - 15 179) and minke whales was 1,544 ( 95% CI: 1,221 - 1,953). These estimates agreed roughly with those reported from a designed survey conducted in the region during the previous austral summer. These estimates assumed that all animals on the trackline were detected, but preliminary results suggest that any negative bias due to violation of this assumption was likely small. Similarly, current methodological limitations prohibit inclusion of all known sources of uncertainty in the favored variance estimator. Meanwhile, our approach can be seen generally as an inexpensive pilot study to identify areas of predicted high density that could be targeted to: inform stratified designs for future line transect surveys, making them less expensive and more precise; increase efficiency of future photo-identification or biopsy studies; identify candidate time-area fisheries closures to minimize by-catch; or direct ecotourism activities. The techniques are likely to apply to areas where funding is limiting, where cetacean studies or wilderness-based tourism are just beginning, or in regions where even a very rough estimate of animal abundance is needed for conservation or management purposes.
Thu, 01 Jun 2006 00:00:00 GMThttp://hdl.handle.net/10023/28572006-06-01T00:00:00ZWilliams, RobertHedley, Sharon L.Hammond, Philip StevenInformation on animal abundance and distribution is at the cornerstone of many wildlife and conservation strategies. However, these data can be difficult and costly to obtain for cetacean species. The expense of sufficient ship time to conduct design-unbiased line transect surveys may be simply out of reach for researchers in many countries, which nonetheless grapple with problems of conservation of endangered species, by-catch of small cetaceans in commercial fisheries, and progression toward ecosystem-based fisheries management. Recently developed spatial modeling techniques show promise for estimating wildlife abundance using non-randomized surveys, but have yet to receive much field-testing in areas where designed surveys have also been conducted. Effort and sightings data were collected along 9 650 km of transects aboard ships of opportunity in the Southern Ocean during the austral summers of 2000 - 2001 and 2001 - 2002. Generalized additive models with generalized cross-validation were used to express heterogeneity of cetacean sightings as functions of spatial covariates. Models were used to map predicted densities and to estimate abundance of humpback, minke, and fin whales in the Drake Passage and along the Antarctic Peninsula. All species' distribution maps showed strong density gradients, which were robust to jackknife resampling when each of 14 trips was removed sequentially with replacement. Looped animations of model predictions of whale density illustrate uncertainty in distribution estimates in a way that is informative to non-scientists. The best abundance estimate for humpback whales was 1 829 (95% CI: 978- 3 422). Abundance of fin whales was 4 487 ( 95% CI: 1 326 - 15 179) and minke whales was 1,544 ( 95% CI: 1,221 - 1,953). These estimates agreed roughly with those reported from a designed survey conducted in the region during the previous austral summer. These estimates assumed that all animals on the trackline were detected, but preliminary results suggest that any negative bias due to violation of this assumption was likely small. Similarly, current methodological limitations prohibit inclusion of all known sources of uncertainty in the favored variance estimator. Meanwhile, our approach can be seen generally as an inexpensive pilot study to identify areas of predicted high density that could be targeted to: inform stratified designs for future line transect surveys, making them less expensive and more precise; increase efficiency of future photo-identification or biopsy studies; identify candidate time-area fisheries closures to minimize by-catch; or direct ecotourism activities. The techniques are likely to apply to areas where funding is limiting, where cetacean studies or wilderness-based tourism are just beginning, or in regions where even a very rough estimate of animal abundance is needed for conservation or management purposes.Global analysis of cetacean line-transect surveys : detecting trends in cetacean densityhttp://hdl.handle.net/10023/2747
Measuring the effect of anthropogenic change on cetacean populations is hampered by our lack of understanding about population status and a lack of power in the available data to detect trends in abundance. Often long-term data from repeated surveys are lacking, and alternative approaches to trend detection must be considered. We utilised an existing database of line transect survey records to determine whether temporal trends could be detected when survey effort from around the world was combined. We extracted density estimates for 25 species and fitted generalised additive models (GAMs) to investigate whether taxonomic, spatial or methodological differences among systematic line-transect surveys affect estimates of density and whether we can identify temporal trends in the data once these factors are accounted for. The selected GAM consisted of 2 parts: an intercept term that was a complex interaction of taxonomic, spatial and methodological factors and a smooth temporal term with trends varying by family and ocean basin. We discuss the trends found and assess the suitability of published density estimates for detecting temporal trends using retrospective power analysis. In conclusion, increasing sample size through combining survey effort across a global scale does not necessarily result in sufficient power to detect trends because of the extent of variability across surveys, species and oceans. Instead, results from repeated dedicated surveys designed specifically for the species and geographical region of interest should be used to inform conservation and management.
Mon, 07 May 2012 00:00:00 GMThttp://hdl.handle.net/10023/27472012-05-07T00:00:00ZJewell, Rebecca LucyThomas, LenHarris, Catriona MKaschner, KristinWiff, Rodrigo AlexisHammond, Philip StevenQuick, Nicola JaneMeasuring the effect of anthropogenic change on cetacean populations is hampered by our lack of understanding about population status and a lack of power in the available data to detect trends in abundance. Often long-term data from repeated surveys are lacking, and alternative approaches to trend detection must be considered. We utilised an existing database of line transect survey records to determine whether temporal trends could be detected when survey effort from around the world was combined. We extracted density estimates for 25 species and fitted generalised additive models (GAMs) to investigate whether taxonomic, spatial or methodological differences among systematic line-transect surveys affect estimates of density and whether we can identify temporal trends in the data once these factors are accounted for. The selected GAM consisted of 2 parts: an intercept term that was a complex interaction of taxonomic, spatial and methodological factors and a smooth temporal term with trends varying by family and ocean basin. We discuss the trends found and assess the suitability of published density estimates for detecting temporal trends using retrospective power analysis. In conclusion, increasing sample size through combining survey effort across a global scale does not necessarily result in sufficient power to detect trends because of the extent of variability across surveys, species and oceans. Instead, results from repeated dedicated surveys designed specifically for the species and geographical region of interest should be used to inform conservation and management.A general discrete-time modeling framework for animal movement using multistate random walkshttp://hdl.handle.net/10023/2605
Recent developments in animal tracking technology have permitted the collection of detailed data on the movement paths of individuals from many species. However, analysis methods for these data have not developed at a similar pace, largely due to a lack of suitable candidate models, coupled with the technical difficulties of fitting such models to data. To facilitate a general modeling framework, we propose that complex movement paths can be conceived as a series of movement strategies among which animals transition as they are affected by changes in their internal and external environment. We synthesize previously existing and novel methodologies to develop a general suite of mechanistic models based on biased and correlated random walks that allow different behavioral states for directed (e.g., migration), exploratory (e.g., dispersal), area-restricted (e.g., foraging), and other types of movement. Using this “tool-box” of nested model components, multi-state movement models may be custom-built for a wide variety of species and applications. As a unified state-space modeling framework, it allows the simultaneous investigation of numerous hypotheses about animal movement from imperfectly observed data, including time allocations to different movement behavior states, transitions between states, the use of memory or navigation, and strengths of attraction (or repulsion) to specific locations. The inclusion of covariate information permits further investigation of specific hypotheses related to factors driving different types of movement behavior. Using reversible jump Markov chain Monte Carlo methods to facilitate Bayesian model selection and multi-model inference, we apply the proposed methodology to real data by adapting it to the natural history of the grey seal (Halichoerus grypus) in the North Sea. Although previous grey seal studies tended to focus on correlated movements, we found overwhelming evidence that bias towards haul-out or foraging locations better explained seal movement than simple or correlated random walks. Posterior model probabilities also provided evidence that seals transition among directed, area-restricted, and exploratory movements associated with haul-out, foraging, and other behaviors. With this intuitive framework for modeling and interpreting animal movement, we believe the development and application of bespoke movement models will become more accessible to ecologists and non-statisticians.
Wed, 01 Aug 2012 00:00:00 GMThttp://hdl.handle.net/10023/26052012-08-01T00:00:00ZMcClintock, Brett ThomasKing, RuthThomas, LenMatthiopoulos, JasonMcConnell, Bernie JMorales, JuanRecent developments in animal tracking technology have permitted the collection of detailed data on the movement paths of individuals from many species. However, analysis methods for these data have not developed at a similar pace, largely due to a lack of suitable candidate models, coupled with the technical difficulties of fitting such models to data. To facilitate a general modeling framework, we propose that complex movement paths can be conceived as a series of movement strategies among which animals transition as they are affected by changes in their internal and external environment. We synthesize previously existing and novel methodologies to develop a general suite of mechanistic models based on biased and correlated random walks that allow different behavioral states for directed (e.g., migration), exploratory (e.g., dispersal), area-restricted (e.g., foraging), and other types of movement. Using this “tool-box” of nested model components, multi-state movement models may be custom-built for a wide variety of species and applications. As a unified state-space modeling framework, it allows the simultaneous investigation of numerous hypotheses about animal movement from imperfectly observed data, including time allocations to different movement behavior states, transitions between states, the use of memory or navigation, and strengths of attraction (or repulsion) to specific locations. The inclusion of covariate information permits further investigation of specific hypotheses related to factors driving different types of movement behavior. Using reversible jump Markov chain Monte Carlo methods to facilitate Bayesian model selection and multi-model inference, we apply the proposed methodology to real data by adapting it to the natural history of the grey seal (Halichoerus grypus) in the North Sea. Although previous grey seal studies tended to focus on correlated movements, we found overwhelming evidence that bias towards haul-out or foraging locations better explained seal movement than simple or correlated random walks. Posterior model probabilities also provided evidence that seals transition among directed, area-restricted, and exploratory movements associated with haul-out, foraging, and other behaviors. With this intuitive framework for modeling and interpreting animal movement, we believe the development and application of bespoke movement models will become more accessible to ecologists and non-statisticians.Deadly diving? Physiological and behavioural management of decompression stress in diving mammalshttp://hdl.handle.net/10023/2475
Decompression sickness (DCS; 'the bends') is a disease associated with gas uptake at pressure. The basic pathology and cause are relatively well known to human divers. Breath-hold diving marine mammals were thought to be relatively immune to DCS owing to multiple anatomical, physiological and behavioural adaptations that reduce nitrogen gas (N-2) loading during dives. However, recent observations have shown that gas bubbles may form and tissue injury may occur in marine mammals under certain circumstances. Gas kinetic models based on measured time-depth profiles further suggest the potential occurrence of high blood and tissue N-2 tensions. We review evidence for gas-bubble incidence in marine mammal tissues and discuss the theory behind gas loading and bubble formation. We suggest that diving mammals vary their physiological responses according to multiple stressors, and that the perspective on marine mammal diving physiology should change from simply minimizing N-2 loading to management of the N-2 load. This suggests several avenues for further study, ranging from the effects of gas bubbles at molecular, cellular and organ function levels, to comparative studies relating the presence/absence of gas bubbles to diving behaviour. Technological advances in imaging and remote instrumentation are likely to advance this field in coming years.
Thu, 22 Mar 2012 00:00:00 GMThttp://hdl.handle.net/10023/24752012-03-22T00:00:00ZHooker, Sascha KateFahlman, A.Moore, M. J.Aguilar de Soto, N.Bernaldo de Quiros, Y.Brubakk, A. O.Costa, D. P.Costidis, A. M.Dennison, S.Falke, K. J.Fernandez, A.Ferrigno, M.Fitz-Clarke, J. R.Garner, M. M.Houser, D. S.Jepson, P. D.Ketten, D. R.Kvadsheim, P. H.Madsen, P. T.Pollock, N. W.Rotstein, D. S.Rowles, T. K.Simmons, S. E.Van Bonn, W.Weathersby, P. K.Weise, M. J.Williams, T. M.Tyack, Peter LloydDecompression sickness (DCS; 'the bends') is a disease associated with gas uptake at pressure. The basic pathology and cause are relatively well known to human divers. Breath-hold diving marine mammals were thought to be relatively immune to DCS owing to multiple anatomical, physiological and behavioural adaptations that reduce nitrogen gas (N-2) loading during dives. However, recent observations have shown that gas bubbles may form and tissue injury may occur in marine mammals under certain circumstances. Gas kinetic models based on measured time-depth profiles further suggest the potential occurrence of high blood and tissue N-2 tensions. We review evidence for gas-bubble incidence in marine mammal tissues and discuss the theory behind gas loading and bubble formation. We suggest that diving mammals vary their physiological responses according to multiple stressors, and that the perspective on marine mammal diving physiology should change from simply minimizing N-2 loading to management of the N-2 load. This suggests several avenues for further study, ranging from the effects of gas bubbles at molecular, cellular and organ function levels, to comparative studies relating the presence/absence of gas bubbles to diving behaviour. Technological advances in imaging and remote instrumentation are likely to advance this field in coming years.Beaked whales respond to simulated and actual navy sonarhttp://hdl.handle.net/10023/2458
Beaked whales have mass stranded during some naval sonar exercises, but the cause is unknown. They are difficult to sight but can reliably be detected by listening for echolocation clicks produced during deep foraging dives. Listening for these clicks, we documented Blainville's beaked whales, Mesoplodon densirostris, in a naval underwater range where sonars are in regular use near Andros Island, Bahamas. An array of bottom-mounted hydrophones can detect beaked whales when they click anywhere within the range. We used two complementary methods to investigate behavioral responses of beaked whales to sonar: an opportunistic approach that monitored whale responses to multi-day naval exercises involving tactical mid-frequency sonars, and an experimental approach using playbacks of simulated sonar and control sounds to whales tagged with a device that records sound, movement, and orientation. Here we show that in both exposure conditions beaked whales stopped echolocating during deep foraging dives and moved away. During actual sonar exercises, beaked whales were primarily detected near the periphery of the range, on average 16 km away from the sonar transmissions. Once the exercise stopped, beaked whales gradually filled in the center of the range over 2-3 days. A satellite tagged whale moved outside the range during an exercise, returning over 2-3 days post-exercise. The experimental approach used tags to measure acoustic exposure and behavioral reactions of beaked whales to one controlled exposure each of simulated military sonar, killer whale calls, and band-limited noise. The beaked whales reacted to these three sound playbacks at sound pressure levels below 142 dB re 1 mu Pa by stopping echolocation followed by unusually long and slow ascents from their foraging dives. The combined results indicate similar disruption of foraging behavior and avoidance by beaked whales in the two different contexts, at exposures well below those used by regulators to define disturbance.
Mon, 14 Mar 2011 00:00:00 GMThttp://hdl.handle.net/10023/24582011-03-14T00:00:00ZTyack, Peter L.Zimmer, Walter M. X.Moretti, DavidSouthall, Brandon L.Claridge, Diane E.Durban, John W.Clark, Christopher W.D'Amico, AngelaDiMarzio, NancyJarvis, SusanMcCarthy, ElenaMorrissey, RonaldWard, JessicaBoyd, Ian L.Beaked whales have mass stranded during some naval sonar exercises, but the cause is unknown. They are difficult to sight but can reliably be detected by listening for echolocation clicks produced during deep foraging dives. Listening for these clicks, we documented Blainville's beaked whales, Mesoplodon densirostris, in a naval underwater range where sonars are in regular use near Andros Island, Bahamas. An array of bottom-mounted hydrophones can detect beaked whales when they click anywhere within the range. We used two complementary methods to investigate behavioral responses of beaked whales to sonar: an opportunistic approach that monitored whale responses to multi-day naval exercises involving tactical mid-frequency sonars, and an experimental approach using playbacks of simulated sonar and control sounds to whales tagged with a device that records sound, movement, and orientation. Here we show that in both exposure conditions beaked whales stopped echolocating during deep foraging dives and moved away. During actual sonar exercises, beaked whales were primarily detected near the periphery of the range, on average 16 km away from the sonar transmissions. Once the exercise stopped, beaked whales gradually filled in the center of the range over 2-3 days. A satellite tagged whale moved outside the range during an exercise, returning over 2-3 days post-exercise. The experimental approach used tags to measure acoustic exposure and behavioral reactions of beaked whales to one controlled exposure each of simulated military sonar, killer whale calls, and band-limited noise. The beaked whales reacted to these three sound playbacks at sound pressure levels below 142 dB re 1 mu Pa by stopping echolocation followed by unusually long and slow ascents from their foraging dives. The combined results indicate similar disruption of foraging behavior and avoidance by beaked whales in the two different contexts, at exposures well below those used by regulators to define disturbance.Technical Note: Animal-borne CTD-Satellite Relay Data Loggers for real-time oceanographic data collectionhttp://hdl.handle.net/10023/2039
The increasing need for continuous monitoring of the world oceans has stimulated the development of a range of autonomous sampling platforms. One novel addition to these approaches is a small, relatively inexpensive data-relaying device that can be deployed on marine mammals to provide vertical oceanographic profiles throughout the upper 2000 m of the water column. When an animal dives, the CTD-Satellite Relay Data Logger (CTD-SRDL) records vertical profiles of temperature, conductivity and pressure. Data are compressed once the animal returns to the surface where it is located by, and relays data to, the Argos satellite system. The technical challenges met in the design of the CTD-SRDL are the maximising of energy efficiency and minimising size, whilst simultaneously maintaining the reliability of an instrument that cannot be recovered and is required to survive its lifetime attached to a marine mammal. The CTD-SRDLs record temperature and salinity with an accuracy of better than 0.005 degrees C and 0.02 respectively. However, due to the limited availability of reference data, real-time data from remote places are often associated with slightly higher errors. The potential to collect large numbers of profiles cost-effectively makes data collection using CTD-SRDL technology particularly beneficial in regions where traditional oceanographic measurements are scarce or even absent. Depending on the CTD-SRDL configuration, it is possible to sample and transmit hydrographic profiles on a daily basis, providing valuable and often unique information for a real-time ocean observing system.
Funded by NERC grants NE/E018289/1 and NER/D/S/2002/00426
Tue, 15 Dec 2009 00:00:00 GMThttp://hdl.handle.net/10023/20392009-12-15T00:00:00ZBoehme, LarsLovell, PhilipBiuw, MartinRoquet, F.Nicholson, J.Thorpe, S. E.Meredith, M. P.Fedak, MikeThe increasing need for continuous monitoring of the world oceans has stimulated the development of a range of autonomous sampling platforms. One novel addition to these approaches is a small, relatively inexpensive data-relaying device that can be deployed on marine mammals to provide vertical oceanographic profiles throughout the upper 2000 m of the water column. When an animal dives, the CTD-Satellite Relay Data Logger (CTD-SRDL) records vertical profiles of temperature, conductivity and pressure. Data are compressed once the animal returns to the surface where it is located by, and relays data to, the Argos satellite system. The technical challenges met in the design of the CTD-SRDL are the maximising of energy efficiency and minimising size, whilst simultaneously maintaining the reliability of an instrument that cannot be recovered and is required to survive its lifetime attached to a marine mammal. The CTD-SRDLs record temperature and salinity with an accuracy of better than 0.005 degrees C and 0.02 respectively. However, due to the limited availability of reference data, real-time data from remote places are often associated with slightly higher errors. The potential to collect large numbers of profiles cost-effectively makes data collection using CTD-SRDL technology particularly beneficial in regions where traditional oceanographic measurements are scarce or even absent. Depending on the CTD-SRDL configuration, it is possible to sample and transmit hydrographic profiles on a daily basis, providing valuable and often unique information for a real-time ocean observing system.An International Quiet Ocean Experimenthttp://hdl.handle.net/10023/1909
The effect of noise on marine life is one of the big unknowns of current marine science. Considerable evidence exists that the human contribution to ocean noise has increased during the past few decades: human noise has become the dominant component of marine noise in some regions, and noise is directly correlated with the increasing industrialization of the ocean. Sound is an important factor in the lives of many marine organisms, and theory and increasing observations suggest that human noise could be approaching levels at which negative effects on marine life may be occurring. Certain species already show symptoms of the effects of sound. Although some of these effects are acute and rare, chronic sublethal effects may be more prevalent, but are difficult to measure. We need to identify the thresholds of such effects for different species and be in a position to predict how increasing anthropogenic sound will add to the effects. To achieve such predictive capabilities, the Scientific Committee on Oceanic Research (SCOR) and the Partnership for Observation of the Global Oceans (POGO) are developing an International Quiet Ocean Experiment (IQOE), with the objective of coordinating the international research community to both quantify the ocean soundscape and examine the functional relationship between sound and the viability of key marine organisms. SCOR and POGO will convene an open science meeting to gather community input on the important research, observations, and modeling activities that should be included in IQOE.
Wed, 01 Jun 2011 00:00:00 GMThttp://hdl.handle.net/10023/19092011-06-01T00:00:00ZBoyd, Ian L.Frisk, GeorgeUrban, EdTyack, PeterAusubel, JesseSeeyave, SophieCato, DougSouthall, BrandonWeise, MichaelAndrew, RexAkamatsu, TomonariDekeling, ReneErbe, ChristineFarmer, DavidGentry, RogerGross, TomHawkins, AnthonyLi, FenghuaMetcalf, KathyMiller, James H.Moretti, DavidRodrigo, CristianShinke, TomioThe effect of noise on marine life is one of the big unknowns of current marine science. Considerable evidence exists that the human contribution to ocean noise has increased during the past few decades: human noise has become the dominant component of marine noise in some regions, and noise is directly correlated with the increasing industrialization of the ocean. Sound is an important factor in the lives of many marine organisms, and theory and increasing observations suggest that human noise could be approaching levels at which negative effects on marine life may be occurring. Certain species already show symptoms of the effects of sound. Although some of these effects are acute and rare, chronic sublethal effects may be more prevalent, but are difficult to measure. We need to identify the thresholds of such effects for different species and be in a position to predict how increasing anthropogenic sound will add to the effects. To achieve such predictive capabilities, the Scientific Committee on Oceanic Research (SCOR) and the Partnership for Observation of the Global Oceans (POGO) are developing an International Quiet Ocean Experiment (IQOE), with the objective of coordinating the international research community to both quantify the ocean soundscape and examine the functional relationship between sound and the viability of key marine organisms. SCOR and POGO will convene an open science meeting to gather community input on the important research, observations, and modeling activities that should be included in IQOE.Evaluating the influence of epidemiological parameters and host ecology on the spread of phocine distemper virus through populations of harbour sealshttp://hdl.handle.net/10023/1112
Background: Outbreaks of phocine distemper virus (PDV) in Europe during 1988 and 2002 were responsible for the death of around 23,000 and 30,000 harbour seals, respectively. These epidemics, particularly the one in 2002, provided an unusual opportunity to estimate epidemic parameters for a wildlife disease. There were marked regional differences in the values of some parameters both within and between epidemics. Methodology and Principal Findings: We used an individual-based model of seal movement that allowed us to incorporate realistic representations of space, time and animal behaviour into a traditional epidemiological modelling framework. We explored the potential influence of a range of ecological (foraging trip duration, time of epidemic onset, population size) and epidemiological (length of infectious period, contact rate between infectious and susceptible individuals, case mortality) parameters on four readily-measurable epidemic characteristics (number of dead individuals, duration of epidemic, peak mortality date and prevalence) and on the probability that an epidemic would occur in a particular region. We analysed the outputs as if they were the results of a series of virtual experiments, using Generalised Linear Modelling. All six variables had a significant effect on the probability that an epidemic would be recognised as an unusual mortality event by human observers. Conclusions: Regional and temporal variation in contact rate was the most likely cause of the observed differences between the two epidemics. This variation could be a consequence of differences in the way individuals divide their time between land and sea at different times of the year.
Catriona Harris was supported by a grant from the UK Natural Environment Research Council. The funders had no role in study design, data collections and analysis, decision to publish, or preparation of the manuscript.
Tue, 01 Jul 2008 00:00:00 GMThttp://hdl.handle.net/10023/11122008-07-01T00:00:00ZHarris, Catriona MTravis, J.M.JHarwood, JohnBackground: Outbreaks of phocine distemper virus (PDV) in Europe during 1988 and 2002 were responsible for the death of around 23,000 and 30,000 harbour seals, respectively. These epidemics, particularly the one in 2002, provided an unusual opportunity to estimate epidemic parameters for a wildlife disease. There were marked regional differences in the values of some parameters both within and between epidemics. Methodology and Principal Findings: We used an individual-based model of seal movement that allowed us to incorporate realistic representations of space, time and animal behaviour into a traditional epidemiological modelling framework. We explored the potential influence of a range of ecological (foraging trip duration, time of epidemic onset, population size) and epidemiological (length of infectious period, contact rate between infectious and susceptible individuals, case mortality) parameters on four readily-measurable epidemic characteristics (number of dead individuals, duration of epidemic, peak mortality date and prevalence) and on the probability that an epidemic would occur in a particular region. We analysed the outputs as if they were the results of a series of virtual experiments, using Generalised Linear Modelling. All six variables had a significant effect on the probability that an epidemic would be recognised as an unusual mortality event by human observers. Conclusions: Regional and temporal variation in contact rate was the most likely cause of the observed differences between the two epidemics. This variation could be a consequence of differences in the way individuals divide their time between land and sea at different times of the year.Influence of the physical environment and conspecific aggression on the spatial arrangement of breeding grey sealshttp://hdl.handle.net/10023/1082
Understanding the habitat requirements of a species for breeding is essential for its conservation, particularly if the availability of suitable habitat is a limiting factor for population growth. This is postulated to be the case for grey seals, one of the more abundant marine apex predators in northern European waters. In common with similar studies that have investigated the habitat preferences of breeding grey seals, we use abiotic (topographical, climatological) attributes but, unlike previous work, we also incorporate behavioural variables, particularly the occurrence of aggressive interactions between females and the presence of neighbouring seals. We used two Generalized Additive Models (GAM) in a sequential and iterative fashion. The first model links the occurrence of aggression at particular points in the colony to local topography derived from a Geographical Information System (GIS), presence of neighbouring seal pups and the day of the breeding season. The output of this GAM is used as one of the explanatory variables in a GAM of daily variation in the spatial distribution of births. Although proximity of a birth site to a water source and the presence of neighbouring seal pups both had significant influences on the distribution of newborn pups over time and space, at the scale of the study site it was found that simple rules could predict pup distribution more efficiently than a complex individual-based simulation model. (c) 2007 Elsevier B.V. All rights reserved.
Sat, 01 Dec 2007 00:00:00 GMThttp://hdl.handle.net/10023/10822007-12-01T00:00:00ZHarris, Catriona MMatthiopoulos, JasonHarwood, JohnUnderstanding the habitat requirements of a species for breeding is essential for its conservation, particularly if the availability of suitable habitat is a limiting factor for population growth. This is postulated to be the case for grey seals, one of the more abundant marine apex predators in northern European waters. In common with similar studies that have investigated the habitat preferences of breeding grey seals, we use abiotic (topographical, climatological) attributes but, unlike previous work, we also incorporate behavioural variables, particularly the occurrence of aggressive interactions between females and the presence of neighbouring seals. We used two Generalized Additive Models (GAM) in a sequential and iterative fashion. The first model links the occurrence of aggression at particular points in the colony to local topography derived from a Geographical Information System (GIS), presence of neighbouring seal pups and the day of the breeding season. The output of this GAM is used as one of the explanatory variables in a GAM of daily variation in the spatial distribution of births. Although proximity of a birth site to a water source and the presence of neighbouring seal pups both had significant influences on the distribution of newborn pups over time and space, at the scale of the study site it was found that simple rules could predict pup distribution more efficiently than a complex individual-based simulation model. (c) 2007 Elsevier B.V. All rights reserved.Assessing the effectiveness of conservation measures : resolving the "wicked" problem of the Steller sea lionhttp://hdl.handle.net/10023/1034
“Wicked” problems are those that are complex and that change when solutions are applied. Many conflicts in conservation fall in to this category. The study approached the problem of how to constrain the apparent wickedness of a problem in the conservation management of a species by using simple empirical indicators to carry out iterative assessment of the risk to a population and to document how this risk evolves in relation to the addition of new data and the implementation of management actions. Effects of high levels of uncertainty within data and also concerning population structure were examined through stochastic simulation and by exploration of scenarios. Historical trends in the example used, the Steller sea lion, showed rapid declines in abundance in some regions during the 1980s. The current total population is 130,000-150,000 Steller sea lions through Alaska and British Columbia and this number has been stable since about 1990 in spite of regional differences in population dynamics. Regional differences in the sequence of changes in the number of pups and non-pups, suggested that an internal re-distribution of juveniles could have happened between 1980 and 1990. Current productivity also appears close to the long term mean. Stochastic population projection using various scenarios showed that, based upon this history, the risk of extinction for the population has declined and is below reasonable thresholds for considering the population to be endangered.
Thu, 01 Jul 2010 00:00:00 GMThttp://hdl.handle.net/10023/10342010-07-01T00:00:00ZBoyd, Ian Lamont“Wicked” problems are those that are complex and that change when solutions are applied. Many conflicts in conservation fall in to this category. The study approached the problem of how to constrain the apparent wickedness of a problem in the conservation management of a species by using simple empirical indicators to carry out iterative assessment of the risk to a population and to document how this risk evolves in relation to the addition of new data and the implementation of management actions. Effects of high levels of uncertainty within data and also concerning population structure were examined through stochastic simulation and by exploration of scenarios. Historical trends in the example used, the Steller sea lion, showed rapid declines in abundance in some regions during the 1980s. The current total population is 130,000-150,000 Steller sea lions through Alaska and British Columbia and this number has been stable since about 1990 in spite of regional differences in population dynamics. Regional differences in the sequence of changes in the number of pups and non-pups, suggested that an internal re-distribution of juveniles could have happened between 1980 and 1990. Current productivity also appears close to the long term mean. Stochastic population projection using various scenarios showed that, based upon this history, the risk of extinction for the population has declined and is below reasonable thresholds for considering the population to be endangered.Invasive species control : Incorporating demographic data and seed dispersal into a management model for Rhododendron ponticumhttp://hdl.handle.net/10023/1033
Rhododendron ponticum is a serious invasive alien plant in the British Isles and is of significant conservation and economic concern. Here, we integrate information on both the demographics and spatial dynamics of this species within an individual-based, spatially-explicit model and investigate the effectiveness of different control strategies. Importantly, we simulate seed movement and dispersal using a mechanistic seed dispersal model. We investigate the effectiveness of initiating control at the edge versus the core of the infestation, with and without returning each year to remove seedlings. We compare these results to an age-dependent strategy whereby the oldest plants are removed each year. Age-dependent control, in which the oldest plants were removed first, was the most effective strategy investigated, both in terms of the probability of successful eradication and the number of years taken to control. We demonstrate that this is because the older (and taller) plants towards the core produce more seeds that, on average, travel further. Indeed, our results suggest that the expansion of the invading front is actually driven as much by seeds that disperse long distances from these larger plants as by the seed rain from recently matured plants located much closer to the front. Finally, we investigate the potential use of ‘quarantine lines’ — corridors of unsuitable habitat that are sufficiently wide to contain an infestation, preventing spread to vulnerable areas. This study has provided generic insights into best practice for management based on the current understanding of the biology and ecology of this pernicious, invasive plant.
Funding was provided by the Scottish Higher Education Funding Council and The Carnegie Trust for the Universities of Scotland
Tue, 01 Sep 2009 00:00:00 GMThttp://hdl.handle.net/10023/10332009-09-01T00:00:00ZHarris, Catriona MPark, K.J.Atkinson, R.Edwards, C.Travis, J.M.J.Rhododendron ponticum is a serious invasive alien plant in the British Isles and is of significant conservation and economic concern. Here, we integrate information on both the demographics and spatial dynamics of this species within an individual-based, spatially-explicit model and investigate the effectiveness of different control strategies. Importantly, we simulate seed movement and dispersal using a mechanistic seed dispersal model. We investigate the effectiveness of initiating control at the edge versus the core of the infestation, with and without returning each year to remove seedlings. We compare these results to an age-dependent strategy whereby the oldest plants are removed each year. Age-dependent control, in which the oldest plants were removed first, was the most effective strategy investigated, both in terms of the probability of successful eradication and the number of years taken to control. We demonstrate that this is because the older (and taller) plants towards the core produce more seeds that, on average, travel further. Indeed, our results suggest that the expansion of the invading front is actually driven as much by seeds that disperse long distances from these larger plants as by the seed rain from recently matured plants located much closer to the front. Finally, we investigate the potential use of ‘quarantine lines’ — corridors of unsuitable habitat that are sufficiently wide to contain an infestation, preventing spread to vulnerable areas. This study has provided generic insights into best practice for management based on the current understanding of the biology and ecology of this pernicious, invasive plant.